Japan and more lifeguard duty as American heavy bombers stepped up their attacks on the home islands. She arrived Pearl Harbor 13 June 1945. After advanced training in the Marianas, Jallao departed Guam 31 July to patrol the Sea of Japan. On this, her fourth and final patrol, the submarine sank 6,000-ton freighter Timoko Maru 11 August 1945 (19 survivors were found by 21 August 1945). Four days later hostilities ended; and the ship sailed via Guam to San Francisco, where she arrived 28 September 1945. She was decommissioned at Mare Island 30 September 1946, and entered the Pacific Reserve Fleet. 1953–1956 Jallaos home port was changed to New London in July 1953, for a GUPPY IIA conversion in which she was streamlined and equipped with snorkeling gear and new electric equipment. She recommissioned 4 December 1953. After shakedown in the San Diego area, the submarine departed 12 April for the East Coast, steaming via the Panama Canal to Norfolk, Virginia Joining Submarine Squadron 6, Jallao operated out of Halifax, Nova Scotia during 1954, training with Canadian and American antisubmarine units. In January and February 1955, she took part in fleet exercises in the Caribbean, returning to Norfolk 4 March. Jallaos home port was changed to New London in July 1955 and she got underway with British submarine 7 August to take part in Joint Exercise "New Broom IV". Following this operation, Jallao was deployed to the 6th Fleet and departed for the Mediterranean 9 November 1955. In the months that followed, she helped train Italian Navy ships and took part in fleet exercises, beginning the long voyage home in mid-January 1956. The ship steamed through the Suez Canal, visited several countries of eastern and southern Africa, and crossed the South Atlantic to take part in exercises with Uruguayan and Brazilian destroyers. The veteran submarine returned to New London 16 April. 1957–1967 After having installed the latest in electronic gear, Jallao resumed operations in January 1957. Combined fleet exercises in the Caribbean occupied her through February; and, after coastal antisubmarine operations, she arrived Boston late in July for a short midshipman training cruise. September and October were spent in the North Atlantic on a NATO exercise as the submarine helped strengthen the armed forces of the Atlantic Allies. She returned to New London 24 October 1957. Jallao spent most of 1958 on training exercises off the Atlantic Coast, taking part