German submarine U-402 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down at the Danziger Werft in the city of the same name on 22 April 1940 as yard number 103, launched on 28 December 1940 and was commissioned on 21 May 1941, with Kapitänleutnant Siegfried Freiherr von Forstner in command. For his numerous successes, von Forstner received the Knight's Cross.