HMS Onyx (S21)

HMS Onyx (S21)

HMS Onyx was an Oberon class submarine of the Royal Navy. Originally ordered for the Royal Canadian Navy, Onyx was transferred to the Royal Navy whilst under construction at Cammell Laird shipbuilders in Birkenhead, England. She was launched on August 1966 and commissioned into the Royal Navy in September 1967.

The first commission of the Onyx saw her visit Swansea in South Wales for the investiture of His Royal Highness The Prince of Wales. She also attended the bicentennial celebrations of the United States of America in 1976.