HMS Alderney (P416/S66), was an of the Royal Navy, built by Vickers-Armstrongs at Barrow and launched 25 June 1945 by Mrs Molly Wallis, wife of Sir Barnes Wallis. She was the 12th of the class and was scrapped in 1972.
Like all Amphion-class submarines, Alderney had a displacement of when at the surface and while submerged. She had a total length of , a beam of , and a draught of . The submarine was powered by two Admiralty ML eight-cylinder diesel engines generating a power of each. She also contained four electric motors each producing that drove two shafts. She could carry a maximum of of diesel, although she usually carried between .
The submarine had a maximum surface speed of and a submerged speed of . When submerged, she could operate at for or at for . When surfaced, she was able to travel at or at . She was fitted with ten torpedo tubes, one QF 4 inch naval gun Mk XXIII, one Oerlikon 20 mm cannon, and a .303 British Vickers machine gun. Her torpedo tubes were fitted to the bow and stern, and she could carry twenty torpedoes. Her complement was sixty-one crew members.
Alderney completed three commissions between 1954 and 1963 with the 6th Submarine Squadron at Halifax, Nova Scotia, carrying out exercises with the Royal Canadian Navy and Royal Canadian Air Force. In September 1952 replaced the damaged Alderney, which had developed issues while training with vessels of the Royal Canadian Navy off Bermuda. She was modernised during a long refit in Portsmouth Dockyard between 1956 and 1958. In 1965 she recommissioned for the eighth time and was allocated to the 1st Submarine Squadron at . In 1965 and 1966 she was present at Portsmouth Navy Days. She was decommissioned in 1966 and was broken up at Troon, Scotland on 1 February 1970.