HMS P556

HMS P556 (pennant number P556) was a S1-class submarine of the British Royal Navy. Formerly known as USS S-29.

USS S-29 was transferred to the Royal Navy at New London on 5 June 1942. She arrived at Gibraltar, via Bermuda, in August 1942 to refit, nominally as part of 8th Flotilla. She moved to Plymouth in February 1943, for anti-submarine training role. In November 1943, she moved to Portsmouth for service in the same role.

HMS P556 was damaged by a battery explosion on 27 January 1944, and was decommissioned into reserve in April. She was returned to the United States Navy on 26 January 1945. Sold for scrap to Messrs Pounds, Portsmouth on 24 January 1947.