On September 5, 1950, "Tilefish" departed Pearl Harbor for Japan. From September 28, 1950 through March 24, 1951, the submarine operated out of Japanese ports conducting patrols in Korean waters in support of the United Nations campaign in Korea. She made reconnaissance patrols of La Perouse Strait to keep the Commander, Naval Forces Far East, informed of Soviet seaborne activity in that area. After this tour, the submarine resumed her routine of operations out of Hawaiian and West Coast ports until 1957. Highlights of this period were convoy attack exercises in Hawaiian waters and a goodwill visit to Acapulco, Mexico, early in June 1956.