German submarine U-1204 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. She was ordered on 14 October 1941, and was laid down on 15 May 1943 at F Schichau GmbH, Danzig, as yard number 1574. She was launched on 9 December 1943 and commissioned under the command of Oberleutnant zur See Heinrich Mäueler on 17 February 1944.