# List of ship commissionings in 1940

The list of ship commissionings in 1940 includes a chronological list of ships commissioned in 1940. In cases where no official commissioning ceremony was held, the date of service entry may be used instead.
| Date | Operator | Ship | Class and type | Notes |
| 18 January | Kriegsmarine | U-63 | Type IIC submarine | |
| 1 March | Kriegsmarine | Adolf Vinnen | weather ship | ex-fishing trawler Gustav Adolf Kühling |
| 6 March | United States Navy | Tippecanoe | Patoka-class oiler | |
| unknown date | United States Coast and Geodetic Survey | Explorer | survey ship | entered service in spring 1940 |
| 1 April | French Navy | Richelieu | Richelieu-class battleship | |
| 6 April | Royal Navy | Gladiolus | Flower-class corvette | |
| 20 April | Kriegsmarine | U-120 | Type IIB submarine | |
| 23 April | Royal Norwegian Navy | Honningsvåg | Naval trawler | ex-Malangen, captured from Germany |
| 25 April | United States Navy | Wasp | aircraft carrier | |
| 28 May | Kriegsmarine | U-121 | Type IIB submarine | |
| 13 June | Kriegsmarine | Tiger | torpedo boat | ex-Norwegian Sleipner-class destroyer Tor |
| 15 June | Kriegsmarine | U-137 | Type IID submarine | |
| 17 June | United States Navy | Abbot | Wickes-class destroyer | recommissioned from reserve |
| 27 June | Kriegsmarine | U-138 | Type IID submarine | |
| 8 July | Kriegsmarine | Hessen | weather ship | converted sealer |
| 24 July | Kriegsmarine | U-139 | Type IID submarine | |
| 1 August | Kriegsmarine | Prinz Eugen | Admiral Hipper-class cruiser | |
| 7 August | Kriegsmarine | U-140 | Type IID submarine | |
| 20 August | Kriegsmarine | Bismarck | Bismarck-class battleship | |
| 21 August | Kriegsmarine | U-141 | Type IID submarine | |
| 22 August | Kriegsmarine | Karl Meyer | Karl Meyer-class seaplane tender | completion date |
| 4 September | Kriegsmarine | U-142 | Type IID submarine | |
| 9 September | Royal Navy | Castleton | Town-class destroyer | ex-USS Aaron Ward, commissioned at Halifax upon transfer from the United States Navy under the command of Cmdr. Frank H. E. Skyrme |
| 9 September | Royal Navy | Clare | Town-class destroyer | ex-USS Abel P. Upshur, commissioned at Halifax upon transfer from the United States Navy |
| 18 September | Kriegsmarine | U-143 | Type IID submarine | |
| 23 September | Royal Navy | Charlestown | Town-class destroyer | ex-USS Abbot transferred as part of the destroyers-for-bases deal |
| 24 September | Royal Canadian Navy | St. Clair | Town-class destroyer | |
| 2 October | Kriegsmarine | U-144 | Type IID submarine | |
| 16 October | Kriegsmarine | U-145 | Type IID submarine | |
| 23 October | Royal Navy | Lancaster | Town-class destroyer | Ex-USS Philip |
| 23 October | Royal Navy | Mansfield | Town-class destroyer | Ex-USS Evans |
| 23 October | Royal Navy | Montgomery | Town-class destroyer | Ex-USS Wickes |
| 30 October | United States Navy | Santee | Cimarron-class oiler (1939) | ex-merchant tanker Seakay |
| 30 October | Kriegsmarine | U-146 | Type IID submarine | |
| 4 November | United States Navy | Sangamon | Cimarron-class oiler | ex-Esso Trenton |
| 13 November | Kriegsmarine | U-149 | Type IID submarine | |
| 26 November | Royal Navy | Newark | Town-class destroyer | Ex-USS Ringgold |
| 27 November | Kriegsmarine | U-150 | Type IID submarine | |
| 5 December | Royal Navy | Newmarket | Town-class destroyer | Ex-USS Robinson |
| 5 December | Royal Navy | Newport | Town-class destroyer | Ex-USS Sigourney |
| 5 December | Royal Navy | Richmond | Town-class destroyer | Ex-USS Fairfax |
| 11 December | Kriegsmarine | U-147 | Type IID submarine | |
| 11 December | Royal Navy | King George V | King George V-class battleship | |
| unknown date | Kriegsmarine | Schwabenland | seaplane tender | converted merchant |
| unknown date | Kriegsmarine | August Wriedt | weather ship | ex-FV August Wriedt |