German submarine U-656 was a German Type VIIC U-boat built for the Nazi Germany's Kriegsmarine for service during World War II. She was ordered on 9 October 1939 and the keel laid on 4 September 1940. Construction on U-656 was carried out by Hamburg company Howaldtswerke as yard number 805. She was launched on 8 July 1941 and commissioned on 17 September 1941.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-656 had a displacement of 769t when at the surface and 871t while submerged. She had a total length of 67.1m (220.1feet), a pressure hull length of 50.5m (165.7feet), a beam of 6.2m (20.3feet), a height of 9.6m (31.5feet), and a draught of 4.74m (15.55feet). The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of NaNPS for use while surfaced, two Siemens-Schuckert GU 343/38–8 double-acting electric motors producing a total of 750PS for use while submerged. She had two shafts and two 1.23abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-656 was fitted with five 53.30NaN0 torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.82NaN2 SK C/35 naval gun, 220 rounds, and a 2sp=usNaNsp=us C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.
U-656 went into service initially with 5th U-boat Flotilla for training from 17 September 1941 until 31 December 1941. She moved into operational service with 1st U-boat Flotilla on 1 January 1942, and was commanded by Kapitänleutnant Ernst Kröning.
U-656 made two patrols, but did not sink any ships. Her first patrol lasted almost two weeks: after departing Kiel on 15 January 1942, she put in at Brest, France on 28 January. The submarine departed Brest on 4 February, but never completed her second patrol. She was sunk with all hands by depth charges dropped by a United States Navy PBO-1 Hudson of Patrol Squadron 82 (VP-82) on 1 March 1942 south of Cape Race, Newfoundland. U-656 became the first U-boat to be sunk by the U.S. Navy in World War II.