In 1945, after the war in Europe was finished, Cavalier and other destroyers of the 6th Flotilla were detached to the Western Approaches Command and based on the Clyde. In June the 6th Flotilla was allocated to the British Pacific Fleet, and HMS Cavalier was taken in hand for refit at Rosyth. On completion in mid-August, the war with Japan had ended and the 6th Flotilla was ordered to relieve the 11th Destroyer Flotilla on the East Indies Station where Cavalier took part in the bombardment of Surabaja, Java. In June 1946 Cavalier returned to Britain and was reduced to reserve.
HMS Cavalier was refitted at Portsmouth and modernised at Thornycroft's, Southampton, between 1955 and 1957. Her capabilities were enhanced as a general-purpose escort ship. The latest Mk 6M fire control and remote power control were fitted to her guns; her after torpedo tubes were replaced by a deckhouse with two Squid anti-submarine mortars and a twin Mk 5 Bofors anti-aircraft gun fitted above. This modernisation did little to alter her wartime structure with its lattice mast, single funnel and the crew remaining at the mercy of the elements for much of the time. July 1957 was spent in the far east again, joining the 8th Destroyer squadron at Singapore.
