German submarine U-777 was a German Type VIIC U-boat built in World War II, launched on 25 March 1944, and commissioned on 9 May, by its sole commander, Oberleutnant Günter Ruperti. It underwent training with the 31st U-boat Flotilla, but did not participate in any patrols during its five-month career of active service. It was destroyed at 20:02 hours on the night of 15/16 October 1944, during a British air raid on Wilhelmshaven, Germany, at position . One crewman was killed.