The ship undertook her builders and acceptance sea trials over a period of two weeks, during which she steamed for a total of 150 hours, arriving at Chatham on 22 September, where she was de-stored.

Matapan was initially laid up in Gillingham Reach on the River Medway from 28 October 1947 and was subsequently towed to Devonport on 20 July 1948, where she was prepared for preservation in long-term reserve.

[3] Advances in Soviet nuclear submarine performance during the 1960s rendered the existing NATO sonar equipment, which were based on analogue technology of World War II origin and had limited range, obsolescent.

It used pre-formed digital beams at lower frequencies than previous types, that could track many more targets, whilst using fewer ratings to process the information.

Towards the stern, she was fitted with a second funnel to vent the exhaust gases from the generators needed to power the sonar, and a helicopter flight deck on a deckhouse aft.

[5] Upon completion of her sea trials, Matapan entered active service for the very first time, commissioned on 2 February 1973, joining the Admiralty Underwater Weapons Establishment (AUWE), based in Portland.

During these exercises it was reported by P.O.Moore (Petty Officer, Torpedo and Anti-Submarine Instructor) that: "The crew of USS Tullibee, claimed that having our sonar ping them was like having a metal bucket on your head and someone hitting it with a sledgehammer.