German submarine U-654 was a Type VIIC U-boat that was built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 1 June 1940 by Howaldtswerke, Hamburg as yard number 803, launched on 3 May 1941 and commissioned on 5 July 1941 under Korvettenkapitän Hans-Joachim Hesse.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-654 had a displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two Siemens-Schuckert GU 343/38-8 double-acting electric motors producing a total of for use while submerged. She had two shafts and two 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-654 was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one SK C/35 naval gun, 220 rounds, and a C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.
The boat's career began with training at 5th U-boat Flotilla on 5 July 1941, followed by active service on 1 November 1941 as part of the 1st Flotilla for the remainder of her service. In four patrols she sank three merchant ships, for a total of and one warship.
U-654 took part in one wolfpack, namely:
U-654 was sunk on 22 August 1942 in the Caribbean, around 200 miles/300 km north of Panama City, in position , by the depth charges from a United States Army Air Forces Douglas B-18 Bolo aircraft of the 45th Bombardment Squadron. All hands were lost.