List of ship launches in 1921

The list of ship launches in 1921 includes a chronological list of some ships launched in 1921.

	Country	Builder	Location	Ship	Class / type	Notes
5 January	United States	Bethlehem Shipbuilding Corporation	San Francisco, California	S-40	S-class submarine
7 February	United States	Portsmouth Navy Yard	Kittery, Maine	S-11	S-class submarine
21 February	United States	Bethlehem Shipbuilding Corporation	San Francisco, California	S-41	S-class submarine
22 March	United States	New York Shipbuilding Corporation	Camden, New Jersey	Colorado	Colorado-class battleship
9 April	United Kingdom of Great Britain and Ireland	Swan Hunter & Wigham Richardson	Wallsend	Laconia	Ocean liner
19 May	Belgium	J Cockerill SA	Hoboken	Elisabethville	Cargo liner	For Compagnie Belge Maritime du Congo
23 May	United States	Todd Drydock and Construction Company	Tacoma, Washington	Cincinnati	Omaha-class cruiser
16 June	Norway	Naval Shipyard	Horten	Stegg	Trygg-class torpedo boat
4 August	United States	Portsmouth Navy Yard	Kittery, Maine	S-12	S-class submarine
1 September	United Kingdom of Great Britain and Ireland	Bartram & Sons	South Dock, Sunderland	Ramsay	Cargo ship
1 September	United States	New York Shipbuilding Corporation	Camden, New Jersey	Washington	Colorado-class battleship
14 September	United States	New York Shipbuilding Corporation	Camden, New Jersey	Empire Arrow	Tanker	For Standard Transportation Co Inc.
29 September	United States	New York Shipbuilding Corporation	Camden, New Jersey	Richmond	Omaha-class cruiser
20 October	United States	Portsmouth Navy Yard	Kittery, Maine	S-13	S-class submarine
29 October	United States	Mare Island Naval Shipyard	Vallejo, California	Decatur	Clemson-class destroyer
October 29	United States	Mare Island Naval Shipyard	Vallejo, California	Perry	Clemson-class destroyer
17 November	United States	Newport News Shipbuilding	Newport News, Virginia	West Virginia	Colorado-class battleship
15 December	United States	William Cramp and Sons	Philadelphia, Pennsylvania	Concord	Omaha-class cruiser
Unknown date	United Kingdom of Great Britain and Ireland	Eltringham's Ltd	Willington on Tyne	Dalewood	Cargo ship	W France, Fenwick & Co Ltd
Unknown date	Germany	Nobiskrug Werft GmbH	Rendsburg	Elbe	Cargo ship	For Bugsier Reederei & Bergungs AG
Unknown date	Germany	Stettiner Oderwerke AG	Stettin	Günther Russ	Coaster	For Schiffart-und Assekuranz Gesellschaft GmbH
Unknown date	Germany	Stettiner Oderwerke AG	Stettin	Johannes C Russ	Coaster	For Schiffart-und Assekuranz Gesellschaft GmbH
Unknown date	Germany	Deutsche Werke	Kiel	Margarethe	Schooner	For Ernst Simon AG
Unknown date	Germany	Howaldtswerke	Kiel	Possehl	Cargo ship	Lübeck Line
Unknown date	Germany	Stettiner Oderwerke	Stettin	Wilhelm Russ	Coaster	Schiffart-und Assekuranz Gesellschaft GmbH