List of shipwrecks in October 1917

The list of shipwrecks in October 1917 includes some ships sunk, foundered, grounded, or otherwise lost during October 1917.

October 1917
Mon	Tue	Wed	Thu	Fri	Sat	Sun
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30	31		Unknown date

1 October

• Carrabin (United Kingdom of Great Britain and Ireland): World War I: The barque was torpedoed and sunk in the Atlantic Ocean south of Daunt Rock by SM U-96 (Kaiserliche Marine). Her crew survived.
• Etna (Kingdom of Italy): World War I: The cargo ship was sunk in the Atlantic Ocean 110 nautical miles (200 km) south east of Madeira, Portugal (33°41′N 15°25′W) by SM U-151 (Kaiserliche Marine).
• Ludovicos (United Kingdom of Great Britain and Ireland): World War I: The sailing vessel was scuttled in the Mediterranean Sea 7 nautical miles (13 km) south of Pissouri, Cyprus by SM U-73 (Kaiserliche Marine).
• Mersario (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean (86 nautical miles (159 km) west by north of Cape Spartel, Morocco by SM U-39 (Kaiserliche Marine) with the loss of three crew.
• USRC Mohawk (United States Coast Guard): The cutter collided with Vennacher (United Kingdom of Great Britain and Ireland) in the Atlantic Ocean off Sandy Hook, New Jersey and sank. Her crew were rescued.
• Neuilly (France): World War I: the barque was scuttled in the Atlantic Ocean 450 nautical miles (830 km) south west of Penmarc'h, Finistère (46°14′N 13°07′W) by SM U-90 (Kaiserliche Marine). Her crew survived.
• Normanton (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 115 nautical miles (213 km) west of Cape Spartel (35°26′N 8°15′W) by SM U-39 (Kaiserliche Marine). Her crew survived.
• Saint Pierre (France): World War I: The schooner was shelled and sunk in the Atlantic Ocean 60 nautical miles (110 km) north west of Ouessant, Finistère (48°30′N 10°00′W) by SM U-60 (Kaiserliche Marine).

2 October

• Almora (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 100 nautical miles (190 km) west by north of Cape Spartel, Morocco (35°37′N 7°46′W) by SM U-39 (Kaiserliche Marine). Her crew survived.
• HMS Drake (Royal Navy): World War I: The Drake-class cruiser was torpedoed and sunk off Rathlin Island, County Antrim by SM U-79 (Kaiserliche Marine) with the loss of eighteen of her 900 crew.
• Hikosan Maru (Japan): World War I: The cargo ship was sunk in the Atlantic Ocean west of Cape Spartel (35°28′N 8°37′W) by SM U-39 (Kaiserliche Marine). Her crew survived.
• Imera (Kingdom of Italy): World War I: The cargo ship was torpedoed and sunk in the Ionian Sea off Santa Maria di Leuca, Lecce by SM UB-48 (Kaiserliche Marine).
• Lugano (United Kingdom of Great Britain and Ireland): World War I: The cargo ship struck a mine and sank in the Atlantic Ocean 2 nautical miles (3.7 km) south west of Bull Point, County Antrim. Her crew survived.
• Nuceria (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 120 nautical miles (220 km) west of Cape Spartel (35°27′N 8°25′W) by SM U-39 (Kaiserliche Marine) with the loss of two crew.
• Trafaria (Portugal): World War I: The cargo ship was sunk in the Atlantic Ocean 20 nautical miles (37 km) north north west of Cape Ortegal, Spain (45°35′N 9°3′W) by SM U-88 (Kaiserliche Marine).
• Viajante (Portugal): World War I: The barque was sunk in the Atlantic Ocean 170 nautical miles (310 km) north west of Porto Santo Island, Madeira (35°40′N 15°10′W) by SM U-151 (Kaiserliche Marine).
• Willing Boys (United Kingdom of Great Britain and Ireland): World War I: The fishing smack struck a mine and sank in the North Sea with the loss of five of her crew.

3 October

• Annie F. Conlon (United States): World War I: The sailing vessel was damaged in the Atlantic Ocean 15 nautical miles (28 km) south east of the Isles of Scilly, United Kingdom by SM UC-47 (Kaiserliche Marine). Her crew survived, but she was subsequently declared a constructive total loss.
• Baron Blantyre (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 60 nautical miles (110 km) north west by west of Cape Finisterre, Spain (43°15′N 10°30′W) by SM U-88 (Kaiserliche Marine) with the loss of a crew member.
• Britannia (United Kingdom of Great Britain and Ireland): The sloop foundered in the North Sea with the loss of a crew member.
• Elisa (Kingdom of Italy): World War I: The brigantine was shelled and sunk in the Tyrrhenian Sea off Cape Figari, Sardinia (41°07′N 9°47′E) by SM UC-35 (Kaiserliche Marine).
• Ellerslie (United Kingdom of Great Britain and Ireland): The collier was lost on this date.
• Giuseppe Ferrante (Kingdom of Italy): World War I: The sailing vessel was sunk in the Tyrrhenian Sea off Isola del Giglio by SM UC-35 (Kaiserliche Marine).
• Hurst (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in St. George's Channel 2.25 nautical miles (4.17 km) west by north of Skokholm, Pembrokeshire by SM U-96 (Kaiserliche Marine). Her crew survived.
• Jane Knox (United Kingdom of Great Britain and Ireland): The schooner was wrecked in the Bristol Channel off Porthcawl, Glamorgan with the loss of all hands.
• Jeanne (France): World War I: The three-masted schooner was sunk in the Bay of Biscay (46°43′N 13°23′W) by SM U-90 (Kaiserliche Marine) with the loss of six of her crew.
• Memling (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Bay of Biscay off Brest, Finistère, France by a Kaiserlich Marine submarine.
• Saint Antoine (France): World War I: The schooner was sunk in the Bay of Biscay (47°30′N 9°40′W) by SM U-60 (Kaiserliche Marine).
• Stella (France): World War I: The schooner was shelled and sunk in the Bay of Biscay (47°30′N 9°40′W) by SM U-60 (Kaiserliche Marine) with the loss of ten crew.
• Tasmania (Kingdom of Italy): World War I: The cargo ship was sunk in the English Channel 8 nautical miles (15 km) west of Prawle Point, Devon, United Kingdom by SM UC-65 (Kaiserliche Marine).
• SM UC-14 (Kaiserliche Marine): World War I: The Type UC I submarine struck a mine and sank in the North sea off Zeebrugge, West Flanders, Belgium (51°31′50″N 3°08′45″E) with the loss of all fourteen crew.

4 October

• Bygdønes (Norway): World War I: The cargo ship was captured in the Atlantic Ocean by SM U-151 (Kaiserliche Marine). She was scuttled the next day 65 nautical miles (120 km) north west of Porto Santo Island, Madeira, Portugal. Her crew survived.
• Citta di Bari (Kingdom of Italy): World War I: The passenger ship was sunk in the Ionian Sea 37 nautical miles (69 km) off Paxos, Greece by SM UB-48 (Kaiserliche Marine).
• Constantinos Embiricos (Greece): World War I: The cargo ship was sunk in the Gulf of Lyon off the Île du Planier, Bouches-du-Rhône, France (42°47′N 4°10′E) by SM U-32 (Kaiserliche Marine). Her crew survived.
• Itasca (United States): The cargo ship foundered in the Atlantic Ocean.
• Nicolaos Roussos (Greece): The cargo ship was torpedoed and sunk in the Gulf of Lyon (42°46′N 4°11′E) by SM U-32 (Kaiserliche Marine).
• Perseverance (United Kingdom of Great Britain and Ireland): World War I: The fishing smack was shelled and sunk in the Atlantic Ocean 15 nautical miles (28 km) west of the Eddystone Lighthouse by SM UB-35 (Kaiserliche Marine). Her crew survived.
• USS Rehoboth (United States Navy): The patrol vessel sprang a leak in the English Channel. Her crew were rescued by HMS Castor (Royal Navy, which scuttled the ship.
• Rupee (United Kingdom of Great Britain and Ireland): World War I: The fishing smack was shelled and sunk in the Bristol Channel 10 nautical miles (19 km) north of Lundy Island, Devon by SM U-96 (Kaiserliche Marine) with the loss of four crew.
• Stella (French Navy): World War I: The naval trawler struck a mine and sank in the Mediterranean Sea off Cape Bougaroni, Algeria.
• Young Clifford (United Kingdom of Great Britain and Ireland): World War I: The fishing smack was shelled and sunk in the Bristol Channel 12 nautical miles (22 km) north of Lundy Island by SM U-96 (Kaiserliche Marine). Her crew survived.

5 October

• Apache: (France): The auxiliary barque foundered on this date with the loss of fifteen of her nineteen crew.
• Bontnewydd (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 60 nautical miles (110 km) north north east of Marsa Susa, Libya (33°53′N 22°19′E) by SM U-28 (Austro-Hungarian Navy) with the loss of three of her crew.
• Forestmoor (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 54 nautical miles (100 km) west north west of Cape Spartel, Morocco (35°57′N 7°03′W) by SM UB-51 (Kaiserliche Marine) with the loss of 22 crew.
• Galley (United Kingdom of Great Britain and Ireland): The ketch foundered on this date. Her crew survived.
• SM UB-41 (Kaiserliche Marine): World War I: The Type UB II submarine struck a mine and sank in the North Sea off Scarborough, Yorkshire, United Kingdom with the loss of all 22 crew.

6 October

• Bedale (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Atlantic Ocean 25 nautical miles (46 km) south east by south of Mine Head, Cornwall by SM U-96 (Kaiserliche Marine) with the loss of three of her crew.
• Civilian (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 15 nautical miles (28 km) north of Alexandria, Egypt by SM UC-74 (Kaiserliche Marine) with the loss of two of her crew.
• Lamartine (France): World War I: The barquentine was shelled and sunk in the Atlantic Ocean 60 nautical miles (110 km) south west of The Lizard, Cornwall by SM UC-69 (Kaiserliche Marine).
• SMS T54 (Kaiserliche Marine): World War I: The S7-class torpedo boat struck a mine and sank in the Baltic Sea with the loss of seven of her crew.
• Victorine (France): World War I: The barque was shelled and damaged in the Atlantic Ocean 96 nautical miles (178 km) north west of Cape Ortegal, Spain (44°50′N 9°30′W) by SM U-88 (Kaiserliche Marine).She sank the next day.

7 October

• Alcyon (United Kingdom of Great Britain and Ireland): World War I: The sailing vessel was scuttled in the English Channel 12 nautical miles (22 km) west north west of Boulogne, Pas-de-Calais, France by SM UB-57 (Kaiserliche Marine). Her crew survived.
• Georgios (Greece): World War I: The barque was sunk in the Mediterranean Sea north east of Misrata, Libya by SM UC-73 (Kaiserliche Marine).
• Reliance (United Kingdom of Great Britain and Ireland): World War I: The drifter struck a mine and sank in the North Sea with the loss of ten of her crew.
• SM U-106 (Kaiserliche Marine): World War I: The Type U 93 submarine struck a mine and sank in the North Sea 40 nautical miles (74 km) north of Terschelling, Friesland, Netherlands with the loss of all 41 crew.

8 October

• Aylevarroo (United Kingdom of Great Britain and Ireland): World War I: The coaster was sunk in the Atlantic Ocean off Ballycottin Island, County Cork (51°45′N 7°51′W) by SM U-57 (Kaiserliche Marine) with the loss of all twenty crew.
• HMT Ben Heilem (Royal Navy): The naval trawler was lost on this date.
• Greldon (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in St. George's Channel 7 nautical miles (13 km) east north east of the North Arklow Lightship (United Kingdom of Great Britain and Ireland) by SM U-96 (Kaiserliche Marine) with the loss of 28 crew.
• Memphian (United Kingdom of Great Britain and Ireland): World War I: The cargo liner was torpedoed and sunk in St. George's Channel 7 nautical miles (13 km) east north east of the North Arklow Lightship (United Kingdom of Great Britain and Ireland) by SM U-96 (Kaiserliche Marine) with the loss of 32 crew.
• Richard de Larrinaga (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 15 nautical miles (28 km) south east of Ballycottin Island by SM U-57 (Kaiserliche Marine) with the loss of 35 crew.

9 October

• HMS Champagne (Royal Navy): World War I: The armed merchant cruiser was torpedoed and sunk in the Irish Sea 8 nautical miles (15 km) south west of the Calf of Man, Isle of Man (54°17′N 5°10′W) by SM U-96 (Kaiserliche Marine) with the loss of 58 of her 305 crew. Survivors were rescued by the Peel and Port St. Mary Lifeboats.
• Main (United Kingdom of Great Britain and Ireland): World War I: The coaster was shelled and sunk in Luce Bay 1.5 nautical miles (2.8 km) east of Drummore, Wigtownshire by SM UC-75 (Kaiserliche Marine) with the loss of twelve of her crew. She was refloated on 7 August 1920, repaired, and returned to service in August 1922.
• Nervier (Belgium): World War I: The cargo ship was torpedoed, shelled and damaged off the Orkney Islands by SM U-101 (Kaiserliche Marine). She sank on 12 October with loss of all hands.
• Niki (Greece): World War I: The coaster was sunk in the Ionian Sea 30 nautical miles (56 km) north of Cape Matapan by SM UB-48 (Kaiserliche Marine). Her crew survived.
• Peshawur (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Irish Sea 7 nautical miles (13 km) south east of Ballyquintin Point, County Down by SM U-96 (Kaiserliche Marine) with the loss of eleven of her crew.
• Poldown (United Kingdom of Great Britain and Ireland): World War I: The collier struck a mine and sank in the Atlantic Ocean 2 nautical miles (3.7 km) west south west of Trevose Head, Cornwall (50°31′N 5°05′W) by SM UC-51 (Kaiserliche Marine) with the loss of eighteen of her crew.
• San Blas (Panama): The cargo ship sank at Bocas Town, Bocas del Toro.

10 October

• HMS Bostonian (Royal Navy): World War I: The escort ship was torpedoed and sunk in the English Channel 34 nautical miles (63 km) south by east of Start Point by SM U-53 (Kaiserliche Marine) with the loss of four crew.
• Gowrie (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 14 nautical miles (26 km) north east of Cherbourg, Seine-Maritime, France by SM U-53 (Kaiserliche Marine). Her crew survived.
• Transporteur (France): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 30 nautical miles (56 km) off Malta (35°29′N 14°58′E) by SM U-32 (Kaiserliche Marine) with the loss of a crew member.
• HMT Waltham (Royal Navy): The naval trawler was lost on this date.

11 October

• Aghios Georgios (Russian Empire): World War I: The ship was sunk in the Black Sea by SM UB-42 (Kaiserliche Marine).
• Baychattan (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 0.5 nautical miles (930 m) south south west of Prawle Point, Devon by SM UC-50 (Kaiserliche Marine). Her crew survived.
• Cayo Bonito (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Gulf of Genoa 4 nautical miles (7.4 km) east north east of Savona, Liguria, Italy (44°14′N 8°30′E) by SM UC-35 (Kaiserliche Marine) with the loss of six of her crew.
• Elve (United Kingdom of Great Britain and Ireland): World War I: The coaster was shelled and sunk in the Atlantic Ocean off Cape Finisterre, Spain (46°23′N 11°19′W) by SM U-22 (Kaiserliche Marine). Her 29 crew took to the lifeboats but did not survive.
• Italia (Kingdom of Italy): World War I: The cargo ship was sunk in the Gulf of Genoa 4 nautical miles (7.4 km) east north east of Savona (44°14′N 8°30′E) by SM UC-35 (Kaiserliche Marine).
• Joshua (United Kingdom of Great Britain and Ireland): World War I: The sailing vessel was scuttled in the English Channel west of the Isle of Wight by SM UB-57 (Kaiserliche Marine) with the loss of three crew.
• HMY Kethailes (Royal Navy): The naval yacht collided with another vessel and sank in the Irish Sea off the Blackwater Lightship (United Kingdom of Great Britain and Ireland).
• Lewis Luckenbach (United States): World War I: The cargo ship was sunk in the English Channel 10 nautical miles (19 km) west of the Île Vierge, Finistère, France (48°47′N 4°43′W) by SM U-53 (Kaiserliche Marine) with the loss of ten crew.
• Lovli (Kingdom of Italy): World War I: The cargo ship was sunk in the Gulf of Genoa (44°14′N 8°29′E) by SM UC-35 (Kaiserliche Marine).
• Mira (United Kingdom of Great Britain and Ireland): World War I: The tanker struck a mine and sank in the English Channel 4 nautical miles (7.4 km) off Beachy Head, East Sussex (50°41′N 0°09′E). Her crew survived.
• Panormitis (France): World War I: The sailing vessel was sunk in the Mediterranean Sea off the coast of Egypt by SM UC-74 (Kaiserliche Marine). Her crew survived.
• Rhodesia (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Bristol Channel 7 nautical miles (13 km) south east by south of the Coningbeg Lightship (United Kingdom of Great Britain and Ireland) by SM U-61 (Kaiserliche Marine) with the loss of four crew.

12 October

• Cape Corso (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and damaged in the Irish Sea 9 nautical miles (17 km) off the St. Govan Lightship (United Kingdom of Great Britain and Ireland) by SM U-57 (Kaiserliche Marine) with the loss of thirteen crew. Although she subsequently broke her back, she was repaired and returned to service.
• Georgios Markettos (Greece): World War I: The cargo ship was sunk in the Irish Sea 4 nautical miles (7.4 km) off the St. Govan Lightship (United Kingdom of Great Britain and Ireland) by SM U-57 (Kaiserliche Marine). Her crew survived.
• Peebles (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 14 nautical miles (26 km) off Flamborough Head, Yorkshire by SM UB-18 (Kaiserliche Marine). Her crew survived.
• Themis (Norway): World War I: The cargo ship was sunk in the Mediterranean Sea 22 nautical miles (41 km) north of Cape Bon, Algeria (37°26′N 11°04′E) by SM UB-51 (Kaiserliche Marine).
• W. M. Barkley (United Kingdom of Great Britain and Ireland): World War I: The coaster was torpedoed and sunk in the Irish Sea 7 nautical miles (13 km) east of the Kish Lightship (United Kingdom of Great Britain and Ireland) by SM UC-75 (Kaiserliche Marine) with the loss of four of her crew.

13 October

• Alavi (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Mediterranean Sea 6 nautical miles (11 km) north east of Cape Palos, Murcia, Spain (37°40′N 0°34′W) by SM U-35 (Kaiserliche Marine) with the loss of thirteen crew.
• Bethel (Norway): World War I: The sailing vessel was sunk in the North Sea (56°08′N 0°58′E) by SM UB-58 (Kaiserliche Marine). Her crew survived.
• Caprera (Kingdom of Italy): World War I: The cargo ship was sunk in the Atlantic Ocean 60 nautical miles (110 km) west of Casablanca, Morocco (33°53′N 8°45′W) by SM U-151 (Kaiserliche Marine). Her 45 crew were rescued by Ernesto (Spain).
• Despina G. Michalinos (Greece): World War I: The cargo ship was sunk in the Mediterranean Sea off Carthagena, Spain (37°42′N 0°33′W) by SM U-35 (Kaiserliche Marine).
• Doris (Kingdom of Italy): World War I: The cargo ship was sunk in the Mediterranean Sea off Cape Palos (37°46′N 0°38′W) by SM U-35 (Kaiserliche Marine).
• Diu (Portugal): World War I: The cargo ship was sunk in the Atlantic Ocean 4 nautical miles (7.4 km) off the Tuskar Rock, Ireland by SM U-57 (Kaiserliche Marine).
• Eskmere (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Irish Sea 15 nautical miles (28 km) west north west of South Stack, Anglesey by SM UC-75 (Kaiserliche Marine) with the loss of 20 of her crew.
• Esmerelda (Sweden): World War I: The barque was sunk in the North Sea by SM UB-58 (Kaiserliche Marine). Her crew survived.
• Lilla (Kingdom of Italy): World War I: The cargo ship was sunk in the Mediterranean Sea off Carthagena (37°45′N 0°38′W) by SM U-35 (Kaiserliche Marine). Her crew survived.
• Woodburn (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and damaged in the English Channel 3 nautical miles (5.6 km) south east of The Lizard, Cornwall by SM U-62 (Kaiserliche Marine). She was beached at Falmouth. Later refloated, repaired and returned to service.

14 October

• Barbro (Norway): World War I: The cargo ship was sunk in the Atlantic Ocean 13 nautical miles (24 km) north north west of the Île de Batz, Finistère, France (48°55′N 4°14′W) by SM UC-48 (Kaiserliche Marine) with the loss of two of her crew.
• Castro (Greece): World War I: The cargo ship was sunk in the Atlantic Ocean 10 nautical miles (19 km) north north east of Brignogan, Finistère by SM UC-48 (Kaiserliche Marine). Her crew survived.
• HMT Clyde (Royal Navy: The naval trawler collided with another vessel and sank in the English Channel off Sidmouth, Devon.
• Ecaterini C. D. (Greece): World War I: The cargo ship was sunk in the Atlantic Ocean (46°49′N 12°21′W) by SM U-105 (Kaiserliche Marine).
• East Wales (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 8 nautical miles (15 km) south by west of Daunts Rock (51°40′N 8°13′W) by SM U-57 (Kaiserliche Marine) with the loss of three crew.
• Grom (Imperial Russian Navy): The Azard-class destroyer was shelled and damaged in the Gulf of Riga by SMS V100 (Kaiserliche Marine) and was abandoned. She was taken in tow by V100 but consequently foundered.
• Lido G. (United Kingdom of Great Britain and Ireland): World War I: The coaster was sunk in the Mediterranean Sea north east of Misrata, Libya by SM UC-73 (Kaiserliche Marine).
• Semantha (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 10 nautical miles (19 km) north west by north of Cape St. John, Crete, Greece by SM UC-74 (Kaiserliche Marine) with the loss of 32 of her crew.
• SM UC-62 (Kaiserliche Marine): World War I: The Type UC II submarine struck a mine and sank in the North Sea off Zeebrugge, West Flanders, Belgium with the loss of all 26 crew.
• Valparaiso (Kingdom of Italy): World War I: The cargo ship was torpedoed and sunk off Marsa Susa, Libya (36°56′N 21°58′E) by SM UB-48 (Kaiserliche Marine). The wreck was raised in 1928 and sold for scrap in January 1930.

15 October

• HMT Active III (Royal Navy): World War I: The naval trawler struck a mine and sank in the Irish Sea between Grassholm and Skokholm, Pembrokeshire with the loss of all ten crew.
• USS Cassin (United States Navy): World War I: Action of 15 October 1917: The Cassin-class destroyer was torpedoed and damaged in the Atlantic Ocean 20 nautical miles (37 km) south of Mine Head, County Cork, United Kingdom by SM U-61 (Kaiserliche Marine) with the loss of a crew member. She was taken in tow by HMS Snowdrop (Royal Navy). Subsequently repaired and returned to service.
• Garthclyde (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 12 nautical miles (22 km) west of The Lizard, Cornwall (49°55′N 5°30′W) by SM UC-79 (Kaiserliche Marine). Her crew survived.
• Hartburn (United Kingdom of Great Britain and Ireland): World War I: The cargo ship struck a mine and sank in the English Channel 10 nautical miles (19 km) south of Anvil Point, Dorset with the loss of three of her crew.
• Hovde (Norway): World War I: The cargo ship was sunk in the Atlantic Ocean 11 nautical miles (20 km) north west of the Île de Batz, Finistère, France by SM UC-48 (Kaiserliche Marine) with the loss of a crew member.
• Saint Paul (France): World War I: The sailing vessel was shelled and sunk in the Bay of Biscay (46°29′N 10°26′W) by SM U-105 (Kaiserliche Marine) with the loss of a crew member.
• St. Helens (United States): World War I: The cargo ship was sunk in the Atlantic Ocean 100 nautical miles (190 km) west north west of Cape Vilano, Spain (45°57′N 11°19′W) by SM U-105 (Kaiserliche Marine) with the loss of 24 crew.
• White Head (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 14 nautical miles (26 km) north north east of Suda Bay, Crete, Greece (36°13′N 24°33′E) by SM UC-74 (Kaiserliche Marine) with the loss of 23 of her crew.

16 October

• SMS Eber (Kaiserliche Marine): World War I: The gunboat was scuttled at Salvador, Bahia, Brazil.
• Est (Imperial Russian Navy): World War I: The cargo ship was sunk in the Baltic Sea off Ekenäs, Finland (59°51′N 23°46′E) by SM UC-60 (Kaiserliche Marine).
• Jennie E. Righter (United States): World War I: The three-masted schooner was scuttled after being shelled in the Atlantic Ocean north west of Spain (43°54′N 10°02′W) by SM U-22 (Kaiserliche Marine). Her crew survived.
• SMS T56 (Kaiserliche Marine): The S7-class torpedo boat ran aground and sank in the Baltic Sea.

17 October

• Adams (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 6 nautical miles (11 km) south east by east of The Lizard, Cornwall (49°54′N 5°04′W) by SM U-62 (Kaiserliche Marine). Her crew survived.
• USAT Antilles (United States Army): World War I: The troopship was torpedoed and damaged in the Bay of Biscay (48°10′N 11°15′W) by SM U-105 (Kaiserliche Marine) with the loss of 67 lives. Survivors were rescued by USS Corsair (United States Navy) and the ship was scuttled.
• California (United Kingdom of Great Britain and Ireland): World War I: The passenger ship was torpedoed and sunk in the Atlantic Ocean 145 nautical miles (269 km) north north west of Cape Villano, Spain (45°00′N 11°26′W) by SM U-22 (Kaiserliche Marine) with the loss of four lives.
• Habil (Norway): World War I: Action off Lerwick: The coaster was shelled and sunk in the North Sea off Lerwick, Shetland Islands, United Kingdom by SMS Bremse and SMS Brummer) (both Kaiserliche Marine).
• Kristine (Norway): World War I: Action off Lerwick: The coaster was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer) (both Kaiserliche Marine) with the loss of ten of her eleven crew.
• HMT Jean (Royal Navy): The naval trawler was lost in the Mediterranean Sea on this date.
• Manchuria (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 60 nautical miles (110 km) west of Ouessant, Finistère, France by SM U-53 (Kaiserliche Marine) with the loss of 26 crew.
• HMS Mary Rose (Royal Navy): World War I: Action off Lerwick: The M-class destroyer was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer (both Kaiserliche Marine) with the loss of 88 of her 98 crew.
• Polvena (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 25 nautical miles (46 km) north by east of Ouessant (48°55′N 5°10′W) by SM U-53 (Kaiserliche Marine) with the loss of three crew.
• HMT Ruby (Royal Navy): World War I: The naval trawler was torpedoed and sunk in the Atlantic Ocean off Ouessant (48°50′N 5°10′W) by SM UC-79 (Kaiserliche Marine) with the loss of all eighteen crew.
• Silja (Norway): World War I: Action off Lerwick: The cargo ship was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer) (both Kaiserliche Marine).
• Slava (Imperial Russian Navy): World War I: Battle of Moon Sound: The Borodino-class battleship was scuttled in Moon Sound. The wreck was scrapped in 1935.
• Sørhaug (Norway): World War I: Action off Lerwick: The cargo ship was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer) (both Kaiserliche Marine).
• Stella (Denmark): World War I: Action off Lerwick: The coaster was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer) (both Kaiserliche Marine).
• HMS Strongbow (Royal Navy): World War I: Action off Lerwick: The R-class destroyer was shelled and sunk in the North Sea off Lerwick by SMS Bremse and SMS Brummer (both Kaiserliche Marine) with the loss of 47 of her crew.

18 October

• Altair (Norway): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 8 nautical miles (15 km) north east by north of Newquay, Cornwall, United Kingdom (50°31′N 5°17′W) by SM UC-64 (Kaiserliche Marine) with the loss of five of her crew.
• Amsteldam (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 6 nautical miles (11 km) north of Flamborough Head, Yorkshire by SM UB-21 (Kaiserliche Marine) with the loss of four of her crew.
• Anna Scotto (Kingdom of Italy): World War I: The coaster struck a mine and sank in the Mediterranean Sea off Capo Isole delle Correnti, Sicily.
• Cadmus (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 20 nautical miles (37 km) south by east of Flamborough Head by SM UC-47 (Kaiserliche Marine). Her crew survived.
• HMT Comrades (Royal Navy): World War I: The naval trawler struck a mine and sank in the English Channel off Cap d'Antifer, Seine-Maritime, France by SM UC-65 (Kaiserliche Marine). Her crew survived.
• Itero (Norway): The cargo ship foundered in the Atlantic Ocean 500 nautical miles (930 km) west of Cape Finisterre, Spain. Thirty-one of her crew were rescued by a Spanish fishing vessel.
• Lorenzo (Kingdom of Italy): World War I: The cargo ship was sunk in the Atlantic Ocean west of Gibraltar by SM U-35 (Kaiserliche Marine). Her crew survived.
• Macao (Brazil): World War I: The cargo ship was sunk in the Atlantic Ocean 200 nautical miles (370 km) off Cape Finisterre, Spain (45°41′N 10°43′W) by SM U-93 (Kaiserliche Marine).
• Madura (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpeoded and sunk in the Atlantic Ocean 23 nautical miles (43 km) west south west of the Bishop Rock, Isles of Scilly (49°36′N 6°56′W) by SM U-62 (Kaiserliche Marine) with the loss of three crew.
• SMS S64 (Kaiserliche Marine): World War I: The V25-class destroyer struck a mine and sank in the Baltic Sea.
• Sten (United Kingdom of Great Britain and Ireland): World War I: The coaster was torpedoed and sunk in the Atlantic Ocean 5 nautical miles (9.3 km) north of the Godrevy Lighthouse, Cornwall (50°19′N 5°26′W) by SM UC-64 (Kaiserliche Marine) with the loss of nine of her crew.
• SMS T66 (Kaiserliche Marine): World War I: The S66-class torpedo boat struck a mine and sank in the Gulf of Riga.
• Togston (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 20 nautical miles (37 km) south by east of Flamborough Head (53°40′N 0°12′E) by SM UC-47 (Kaiserliche Marine) with the loss of five of her crew.

19 October

• Australdale (Australia): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 165 nautical miles (306 km) north north west of Cape Villano, Spain (45°24′N 11°32′W) by SM U-22 (Kaiserliche Marine) with the loss of 27 crew.
• Britannia (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was sunk in the English Channel off Portland Bill, Dorset by SM UC-75 (Kaiserliche Marine) with the loss of all 22 crew.
• Camswan (United Kingdom of Great Britain and Ireland): The cargo ship collided with another vessel and sank. Her crew were rescued.
• Cupica (United Kingdom of Great Britain and Ireland): World War I: The auxiliary barque was shelled and sunk in the Atlantic Ocean 75 nautical miles (139 km) west by south of the Bishop Rock, Isles of Scilly by SM U-107 and SM UC-79 (both Kaiserliche Marine). Her crew survived.
• Eldra (United Kingdom of Great Britain and Ireland): World War I: The barquentine was scuttled in the English Channel 25 nautical miles (46 km) north west of Le Tréport, Seine-Maritime, France by SM UC-77 (Kaiserliche Marine). Her crew survived.
• Elsiston (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 150 nautical miles (280 km) east by south of Malta (35°40′N 17°28′E) by SM U-14 (Austro-Hungarian Navy) with the loss of a crew member.
• Gemma (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 5 nautical miles (9.3 km) north by west of Flamborough Head, Yorkshire by SM UB-21 (Kaiserliche Marine) with the loss of four of her crew.
• Good Hope (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 125 nautical miles (232 km) east by south of Malta (35°53′N 17°05′E) by SM U-14 (Austro-Hungarian Navy). Her crew survived.
• Harpon (France): World War I: The cargo ship was damaged in the Atlantic Ocean off the coast of Río de Oro (24°22′N 15°50′W) by SM U-151 (Kaiserliche Marine). She was beached but was declared a constructive total loss. Her crew survived.
• Hazelwood (United Kingdom of Great Britain and Ireland): World War I: The cargo ship struck a mine and sank in the English Channel 8 nautical miles (15 km) south by east of Anvil Point, Dorset with the loss of 32 of her crew.
• Ikoma Maru (Japan): World War I: The cargo ship was sunk in the Atlantic Ocean 30 nautical miles (56 km) off Cap Cantin, Morocco by SM U-35 (Kaiserliche Marine). Her crew survived.
• J. L. Luckenbach (United States): World War I: The ocean liner was torpedoed and damaged in the Atlantic Ocean by SM U-62 (Kaiserliche Marine). She was escorted to Le Havre, Seine-Maritime, France by USS Nicholson (United States Navy). Subsequently repaired and returned to service.
• Martha (Denmark): World War I: The barque was shelled and sunk in the North Sea (61°12′N 2°10′W) by SM UB-66 (Kaiserliche Marine). Her ten crew took to the lifeboats but were not rescued.
• HMS Orama (Royal Navy) World War I: The armed merchant cruiser was sunk in the Atlantic Ocean (48°00′N 9°20′W) by SM U-62 (Kaiserliche Marine) with the loss of five crew. Three hundred and five survivors were rescued by USS Jacob Jones (United States Navy).
• Parkhaven (Netherlands): World War I: The cargo ship was sunk in the North Sea 15 nautical miles (28 km) off the Noord Hinder Lightship (Netherlands) (52°16′N 2°46′E) by SM U-53 (Kaiserliche Marine).
• Pera (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 105 nautical miles (194 km) east by north of Marsa Susa, Libya (37°16′N 24°00′E) by SM UB-48 (Kaiserliche Marine) with the loss of a crew member.
• Renard (French Navy): World War I: The naval trawler struck a mine and sank in the Atlantic Ocean south east of Ouessant, Finistère (48°28′N 4°58′W) with the loss of eleven of her crew. Survivors were rescued by 260 (French Navy).
• Slavonic (Russian Empire): World War I: The cargo ship struck a mine and sank in the North Sea off Lerwick, Shetland Islands, United Kingdom.
• Staro (Norway): World War I: The cargo ship was sunk in the Atlantic Ocean (45°00′N 12°07′W) by SM U-22 (Kaiserliche Marine). Her crew survived.
• Teespool (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was damaged in the English Channel 3 nautical miles (5.6 km) south east of Dartmouth, Devon by SM UB-38 (Kaiserliche Marine) with the loss of four of her crew. She was beached but was later refloated.
• Waikawa (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 4 nautical miles (7.4 km) east north east of Start Point, Devon by SM UB-31 (Kaiserliche Marine). Her crew survived.
• War Clover (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 25 nautical miles (46 km) east north east of Pantellaria, Italy (37°00′N 12°35′E) by SM U-64 (Kaiserliche Marine) with the loss of fourteen crew.
• Wellington (United Kingdom of Great Britain and Ireland): World War I: the cargo ship was torpedoed and damaged in the English Channel 5 nautical miles (9.3 km) south south east of Portland Bill by SM UB-40 (Kaiserliche Marine). She was taken in tow by HMT Flo Johnson (Royal Navy and beached at Portland. Later repaired and returned to service.

20 October

• Algarve (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 15 nautical miles (28 km) south west of Portland Bill, Dorset by SM UB-38 (Kaiserliche Marine) with the loss of 21 of her crew.
• Collegian (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 100 nautical miles (190 km) north west by north of Alexandria, Egypt (32°35′N 28°41′E) by SM UB-48 (Kaiserliche Marine). Her crew survived.
• Colorado (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 1.5 nautical miles (2.8 km) east of Start Point, Devon by SM UB-31 (Kaiserliche Marine) with the loss of four crew.
• Ionian (United Kingdom of Great Britain and Ireland): World War I: The passenger ship struck a mine and sank in the Irish Sea 2 nautical miles (3.7 km) west of St. Govan's Head, Pembrokeshire (51°35′N 4°59′W) with the loss of seven lives.
• Leander (Norway): World War I: The cargo ship was sunk in the North Sea 3.5 nautical miles (6.5 km) north north east of Flamborough Head, Yorkshire, United Kingdom by SM UB-57 (Kaiserliche Marine) with the loss of a crew member.
• Moyori Maru (Japan): World War I: The cargo ship was sunk in the Atlantic Ocean 30 nautical miles (56 km) off Cape Barbas, Morocco (22°17′N 17°14′W) by SM U-151 (Kaiserliche Marine).
• Nitedal (Norway): World War I: The cargo ship was sunk in the North Sea 4 nautical miles (7.4 km) east south east of Flamborough Head by SM UB-57 (Kaiserliche Marine) with the loss of twelve crew.
• Norden (Sweden): World War I: The barque was sunk in the North Sea by SM U-57 (Kaiserliche Marine).
• Snetinden (Norway): World War I: The cargo ship was sunk in the Atlantic Ocean north west of Spain (45°35′N 11°10′W) by SM U-22 (Kaiserliche Marine). Her crew survived.
• HMT Thomas Stratten (Royal Navy): World War I: The naval trawler struck a mine and sank in the Atlantic Ocean off the Butt of Lewis, Outer Hebrides with the loss of eight crew.
• Virginia Gentile (Kingdom of Italy): World War I: The sailing vessel was scuttled in the Malta Channel by SM UC-25 (Kaiserliche Marine).
• HMT Vitality (Royal Navy): World War I: The naval trawler struck a mine and sank in the North Sea off Lowestoft, Suffolk with the loss of two of her crew.

21 October

• Anglo Dane (Denmark): World War I: The coaster struck a mine and sank in the North Sea 0.75 nautical miles (1.39 km) off the Bressay Lighthouse, Shetland Islands, United Kingdom with the loss of a crew member.
• Bunty (United Kingdom of Great Britain and Ireland): World War I: The tug struck a mine and sank in the North Sea off Whitby, Yorkshire with the loss of five of her crew.
• Flynderborg (Denmark): World War I: The cargo ship was torpedoed and sunk in the North Sea 3 nautical miles (5.6 km) south east of the Bressay Lighthouse by SM UC-40 (Kaiserliche Marine). Her crew survived.
• Gryfevale (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Atlantic Ocean 10 nautical miles (19 km) off Cap Blanc, Mauritania (21°08′N 17°04′W) by SM U-151 (Kaiserliche Marine). Her crew survived.
• HMS Marmion (Royal Navy): The Admiralty M-class destroyer collided with HMS Tirade (Royal Navy) and sank off the Shetland Islands.
• SMS T66 (Kaiserliche Marine): World War I: The S66-class torpedo boat struck a mine and was damaged in the North Sea off the Belgian coast. She was consequently found to be a total loss.
• Tom Roper (United Kingdom of Great Britain and Ireland): World War I: The topsail schooner was scuttled in the English Channel 20 nautical miles (37 km) south south east of Start Point by SM UC-79 (Kaiserliche Marine) with the loss of a crew member.

22 October

• HMS C32 (Royal Navy): World War I: The C-class submarine ran aground in the Gulf of Riga and was scuttled.
• Novillo (Denmark): World War I: The cargo ship was sunk in the North Sea 8 nautical miles (15 km) north of Scarborough, Yorkshire, United Kingdom by SM UB-57 (Kaiserliche Marine) with the loss of four crew.
• Zillah (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Barents Sea 25 nautical miles (46 km) north east of Kildin Island, Russia by SM U-46 (Kaiserliche Marine) with the loss of eighteen crew.

23 October

• Capo di Monte (Kingdom of Italy): World War I: The cargo ship was sunk in the Mediterranean Sea 100 nautical miles (190 km) west of Heraklion, Crete, Greece (34°53′N 19°50′E) by SM U-14 (Austro-Hungarian Navy).
• HMT Earl Lennox (Royal Navy): World War I: The naval trawler struck a mine and sank south of Islay Sound (55°45′N 5°57′W) with the loss of seven crew.
• Perim (United Kingdom of Great Britain and Ireland): The cargo ship collided with another British merchant ship and sank in the Mediterranean Sea off Barcelona, Spain.
• Seistan (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the North Sea 3.5 nautical miles (6.5 km) north by west of Flamborough Head, Yorkshire (54°09′N 0°08′W) by SM UB-57 (Kaiserliche Marine) with the loss of five of her crew.
• Tredegar Hall (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 4.5 nautical miles (8.3 km) east south east of Flamborough Head by SM UB-57 (Kaiserliche Marine) with the loss of three of her crew.

24 October

• Gallia (Kingdom of Italy): World War I: The cargo ship was sunk in the English Channel 24 nautical miles (44 km) west north west of Portland Bill, Dorset, United Kingdom by SM UB-40 (Kaiserliche Marine). Her crew survived.
• Ilderton (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Barents Sea 35 nautical miles (65 km) north east of Kildin Island, Russia (69°46′N 35°24′E) by SM U-46 (Kaiserliche Marine). Her crew survived.
• Novington (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and damaged in the North Sea 25 nautical miles (46 km) east of Bard Island, Shetland Islands by SM UC-40 (Kaiserliche Marine). She was beached but was later refloated.
• Ulfsborg (Denmark): World War I: The cargo ship was sunk in the Bay of Biscay (46°03′N 1°43′W) by SM UC-63 (Kaiserliche Marine) with the loss of seventeen of her crew.
• Woron (Russian Empire): World War I: The cargo ship was torpedoed and sunk in the North Sea 25 nautical miles (46 km) north east of Lerwick, Shetland Islands by SM UC-40 (Kaiserliche Marine).

25 October

• SMS A32 (Kaiserliche Marine): The A25-class torpedo boat ran aground and sank in the Baltic Sea.
• Erviken (Norway): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 4 nautical miles (7.4 km) south east of Cabo de Gata, Spain by SM U-64 (Kaiserliche Marine) with the loss of a crew member.
• Euston (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the Mediterranean Sea 37 nautical miles (69 km) south west of Cape Matapan, Greece (35°33′N 21°48′E) by SM UC-34 (Kaiserliche Marine) with the loss of a crew member.
• Fannie Prescott (United States): World War I: The schooner was sunk in the Atlantic Ocean 50 nautical miles (93 km) south of Cape Cantin, Morocco by SM U-35 (Kaiserliche Marine).
• Gefion (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 10 nautical miles (19 km) north east of Berry Head, Devon by SM UB-40 (Kaiserliche Marine) with the loss of two of her crew.
• Ness (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was shelled and sunk in the Mediterranean Sea 10 nautical miles (19 km) south east of Cabo de Gata by SM U-64 (Kaiserliche Marine) with the loss of two of her crew.
• Sheaf Blade (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 13 nautical miles (24 km) south east by south of Cabo de Gata by SM U-64 (Kaiserliche Marine) with the loss of two of her crew.
• Wearside (United Kingdom of Great Britain and Ireland): World War I: The cargo ship struck a mine and sank in the North Sea 3 nautical miles (5.6 km) off the Sunk Lightship (United Kingdom of Great Britain and Ireland). Her crew survived.

26 October

• Le Tarn (France): World War I: The cargo ship was sunk in the Mediterranean Sea east of Oran, Algeria (36°15′N 0°03′W) by SM U-64 (Kaiserliche Marine). Her crew survived.
• Sapele (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Atlantic Ocean 100 nautical miles (190 km) north west of Tory Island, County Donegal (55°56′N 11°00′W) by SM U-104 (Kaiserliche Marine) with the loss of three crew.
• SMS T65 (Kaiserliche Marine): World War I: The S7-class torpedo boat struck a mine and sank in the Baltic Sea.

27 October

• D. N. Luckenbach (United States): World War I: The cargo ship was sunk in the Atlantic Ocean (46°34′N 8°34′W) by SM U-93 (Kaiserliche Marine) with the loss of five of her crew.
• Lady Helen (United Kingdom of Great Britain and Ireland): World War I: The coaster was sunk in the North Sea off Robin Hood's Bay, Yorkshire by SM UB-34 (Kaiserliche Marine) with the loss of seven of her crew.
• HMT Strymon (Royal Navy): World War I: The naval trawler struck a naval mine and sank in the North Sea off the Shipwash Lightship (United Kingdom of Great Britain and Ireland) (51°37′N 0°48′E) with the loss of eleven of her crew.

28 October

• Baron Balfour (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Barents Sea 8 nautical miles (15 km) north of Sem Island, Russia by SM U-46 (Kaiserliche Marine). Her crew survived.
• Baron Garioch (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 5 nautical miles (9.3 km) south east of Anvil Point, Dorset (50°36′N 1°43′W) by SM UC-63 (Kaiserliche Marine) with the loss of two of her crew.
• Ferrona (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was scuttled in the Mediterranean Sea 7 nautical miles (13 km) north east of Valencia, Spain (39°28′N 0°10′W) by SM U-64 (Kaiserliche Marine) with the loss of a crew member.

USAT Finland

• USAT Finland (U.S. Army): World War I: The troopship was torpedoed and damaged in the Atlantic Ocean 150 nautical miles (280 km) off Brest, Finistère, France (46°21′N 6°30′W) by SM U-93 (Kaiserliche Marine) with the loss of nine of her crew.
• Marc Fraissinet (France): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 15 nautical miles (28 km) north of Tabarka, Tunisia (37°01′N 8°37′E) by SM UB-50 (Kaiserliche Marine) with the loss of a crew member.
• Redesmere (United Kingdom of Great Britain and Ireland): World War I: The collier was torpedoed and sunk in the English Channel 6 nautical miles (11 km) west south west of St. Catherine's Point, Isle of Wight by SM UB-40 (Kaiserliche Marine) with the loss of nineteen of her crew.
• Senegal (Kingdom of Italy): World War I: The coaster was torpedoed and sunk in the Mediterranean Sea south of Sardinia (37°58′N 8°57′E) by SM UB-50 (Kaiserliche Marine) with the loss of two of her crew.

29 October

• Marne (France): World War I: The coaster was sunk in the English Channel 25 nautical miles (46 km) north east of Barfleur, Manche (50°30′N 1°20′W) by SM UC-63 (Kaiserliche Marine).
• Namur (United Kingdom of Great Britain and Ireland): World War I: The passenger ship was torpedoed and sunk in the Mediterranean Sea 55 nautical miles (102 km) east by south of Gibraltar (36°00′N 4°15′W) by SM U-35 (Kaiserliche Marine) with the loss of a crew member.
• La Epocha (Uruguay): World War I: The barque was scuttled in the Bay of Biscay 30 nautical miles (56 km) south west of the Cordouan Lighthouse, Gironde, France by SM U-93 (Kaiserliche Marine).

30 October

• Liff (Norway): World War I: The cargo ship was sunk in the Bay of Biscay 70 nautical miles (130 km) west of Penmarc'h, Finistère, France (47°37′N 5°13′W) by SM U-93 (Kaiserliche Marine). Her crew survived.

31 October

• Cambric (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the Mediterranean Sea 14 nautical miles (26 km) west of Cape Cherchell, Spain by SM U-35 (Kaiserliche Marine) with the loss of 24 crew.
• Estrellano (United Kingdom of Great Britain and Ireland): World War I: Convoy T 340: The cargo ship was torpedoed and sunk in the Bay of Biscay 14 nautical miles (26 km) west by north of the Île du Pilier, Vendée, France (47°04′N 2°40′W) by SM UC-71 (Kaiserliche Marine) with the loss of three of her crew. Survivors were rescued by La Batailleuse (French Navy).
• Evangelistra (Greece): World War I: The sailing vessel was sunk in the Mediterranean Sea east of Crete (35°49′N 24°05′E) by SM UC-37 (Kaiserliche Marine).
• North Sea (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the English Channel 2.5 nautical miles (4.6 km) south west of Prawle Point, Devon by SM UC-65 (Kaiserliche Marine) with the loss of a crew member.
• Phare (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was torpedoed and sunk in the North Sea 2.5 nautical miles (4.6 km) north of Scarborough, Yorkshire by SM UB-35 (Kaiserliche Marine) with the loss of fourteen of her crew.
• South Bay (United States): The dredger foundered in the Atlantic Ocean off Tampico, Florida.

Unknown date

• HMS Begonia (Royal Navy): The Azalea-class sloop, in use as a Q-ship, collided with SM U-151 (Kaiserliche Marine) and sank in the Mediterranean Sea off Casablanca, Morocco on 2 or 12 October.
• Toledo (United Kingdom of Great Britain and Ireland): World War I: The cargo ship was scuttled in the Baltic Sea to avoid capture by the Germans.
• SM UC-16 (Kaiserliche Marine): World War I: The Type UC II submarine struck a mine and sank in the North Sea off Zeebrugge, West Flanders, Belgium with the loss of all 26 crew.