German submarine U-431 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II.
She was laid down on 4 January 1940 by Schichau-Werke in Danzig as yard number 1472, launched on 2 February 1941 and commissioned on 5 April 1941 under Kapitänleutnant Wilhelm Dommes.