Diablo arrived at Pearl Harbor from New London, Connecticut, on 21 July 1945. She sailed for her first war patrol 10 August with instructions to stop at Saipan for final orders. With the cease fire, her destination was changed to Guam where she arrived 22 August. On the last day of the month she got underway for Pearl Harbor and the East Coast arriving at New York City on 11 October. Except for a visit toCharleston, South Carolina, in October, she remained at New York until 8 January 1946.
Diablo arrived at Naval Station Norfolk, Norfolk, Virginia, her new home port, 5 June 1949, and participated in Operation "Convex" in 1951, and alternated training cruises with duty at the Sonar School at Key West. Her home port became New London in 1952 and she arrived there 17 September to provide training facilities for the Submarine School. From 3 May to 1 June 1954 she was attached to the Operational Development Force at Key West for tests of new weapons and equipment. She participated in Operation "Springboard" in the Caribbean from 21 February to 28 March 1955, and continued to alternate service with the Submarine School with antisubmarine warfare and fleet exercises in the Caribbean and off Bermuda, as well as rendering services to the Fleet Sonar School and Operational Development Force at Key West. Between February and April 1959 she cruised through the Panama Canal along the coasts of Colombia,Ecuador, Peru, and Chile for exercises with South American navies. On 27 May 1960 she entered Philadelphia Naval Shipyard for an overhaul which continued through October 1960.
In 1963, Diablo was transferred to Pakistan on a four-year lease under the terms of the Security Assistance Program. After an extensive overhaul and conversion to Fleet Snorkel configuration in the United States, she was commissioned into the Pakistani Navy as PNS Ghazion 1 June 1964. She reported for duty in Karachi in September of that year.
Ghazi served during the Indo-Pakistani War of 1965 until she was lost in the 1971 war, under unknown circumstances, with all hands on 4 December 1971 just inside the outer channel buoy at Vishakapatnam. Pakistan states that she was destroyed by one of the naval mines she was laying in the harbor, whereas India contends that the destroyerINS Rajput destroyed her with a depth charge attack. According to an Egyptian naval officer whose ship was undergoing refit in the harbour, a "big explosion" occurred in the harbour vicinity and there were no Indian naval ships present until around one hour later.