As with others of her class, she was transferred to the Royal Fleet Auxiliary in 1970, and was crewed by British officers and Hong Kong Chinese sailors.

In 1977 Sir Tristram was used as a guest ship for the Queens Silver Jubilee Fleet Review at Spithead in the Solent.

On 8 June, while transporting men and equipment to Fitzroy Cove alongside the Sir Galahad, Sir Tristram was attacked by Douglas A-4 Skyhawks of the Argentine Air Force's V Brigada Aérea (FAA), each loaded with three 500 lb (230 kg) Mark 82 bombs.

A 500 lb bomb penetrated the deck, but failed to explode immediately, allowing the remaining crew to be evacuated.

[5][6] Sir Tristram then returned to the United Kingdom in 1983 on a heavy lift ship and was extensively rebuilt.