Three years later, "Sea Devil" was again activated; and, on 17 August 1957, she was recommissioned and assigned to SubRon 5 at San Diego, California. For the next year, she conducted training operations off southern California and in the Puget Sound area, then prepared for deployment to the western Pacific. From November 1958 to April 1959, she provided services to Seventh Fleet surface units and to Fleet Marine Force Pacific. In May, she returned to San Diego. On 1 July 1960, she was redesignated an auxiliary submarine with hull classification symbol AGSS-400; and, from that time through 1963, she was primarily engaged in training operations off the West Coast. Only two deployments to the western Pacific during February–August 1961 and June–December 1963 interrupted that schedule.