German submarine U-1225 was a Type IXC/40 U-boat of the German Kriegsmarine during World War II. The submarine was laid down on 28 December 1942 at the Deutsche Werft yard at Hamburg, launched on 21 July 1943, and commissioned on 10 November 1943 under the command of Oberleutnant zur See Ernst Sauerberg. The U-boat then served with 31st U-boat Flotilla, a training unit, until 31 May 1944. She was then transferred to the 2nd U-boat Flotilla for active service.