HMS Adamant was a World War II submarine depot ship.

In 1950, she returned to England, where she remained until 1954 as flagship of the Senior Officer, Reserve Fleet, Portsmouth.

In 1953 she took part in the fleet review to celebrate the Coronation of Queen Elizabeth II.

She then moved further up the Clyde to Faslane on Gare Loch (1959 – 1962), ending the permanent RN presence at Rothesay.

[3] Her design included one-inch torpedo bulkhead 10 feet (3.0 m) inboard, and two-inch steel armour to protect her middle deck.