All Type IXB submarines were ordered by the Nazi Germany's Kriegsmarine between 16 July 1937 and 8 August 1939 as part of Plan Z and the overall German plan of re-armament in violation of the Treaty of Versailles. The design of the IXB submarines came from the initial Type IX submarines, the Type IXA. All contracts for the construction of the submarines were awarded to DeSchiMAG AG Weser, Bremen.