German submarine U-122 was a Type IXB U-boat of the Nazi German Kriegsmarine that operated during World War II. She was ordered on 15 December 1937 and was laid down on 5 March 1939 at AG Weser, Bremen, becoming 'Werk 954'. She was launched on 20 December 1939 and commissioned under her first and only commander, Korvettenkapitän Hans-Günther Looff on 30 March 1940.