HMS Lowestoft was a Rothesay-class or Type 12M class anti-submarine frigate of the British Royal Navy.

Lowestoft was reconstructed in the late 1960s to largely the same pattern as the third group of Leander-class frigates, with new radar and fire control and a hangar and pad for a Westland Wasp helicopter for longer range, anti-submarine, engagement.

In the late 1970s it was converted as the prototype towed array frigate for the Royal Navy, but retained its full armament.

Seacat was not yet ready, and Yarmouth was completed with a single L/60 40 mm Bofors mount aft as a temporary anti-aircraft armament.

On 16 November 1962, a Westland Whirlwind helicopter from the aircraft carrier Hermes with five men aboard, including the politicians Lord Windlesham and John Cronin crashed off St Davids Head.

Lowestoft took part in search operations after the crash, and while three survivors (including Cronin) were rescued by helicopters, Lord Windlesham's body was not found.

Later that day, Lowestoft collided with the cruiser Lion, which was moored under the bridge, having also taken place in the ceremony, in foggy conditions.

[12] In June 1982, as a result of the Falklands War, she was returned to operational service with the 7th Frigate Squadron after a short refit at Portsmouth, serving as guardship at Ascension Island.