German submarine U-904 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. She was ordered on 16 July 1942, and was laid down on 10 September 1942 at Flender Werke AG, Lübeck, as yard number 330. She was launched on 7 August 1943 and commissioned under the command of Leutnant zur See Detlev Fritz on 25 September 1943.