German submarine U-509 was a Type IXC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 1 November 1940 at the Deutsche Werft yard in Hamburg as yard number 305. She was launched on 19 August 1941, and commissioned on 4 November 1941 under the command of Korvettenkapitän Karl-Heinz Wolff. The U-boat served with the 4th U-boat Flotilla for training, before being assigned to the 10th U-boat Flotilla from 1 July 1942, for front-line service.