"Scamp" entered Mare Island Naval Shipyard again in January 1965 for extensive modification. In June 1966 after the installation of the SUBSAFE package and overhaul, she left Mare Island and returned to training cruises in the San Diego operating area. In November she ventured north to Puget Sound for a month of operations and returned to San Diego in December. The nuclear submarine operated out of San Diego for the first six months of 1967. On 28 June, she departed San Diego to join the Seventh Fleet in the western Pacific. She remained in the Far East, participating in fleet operations along the Vietnamese coast, until returning to San Diego on 28 December 1967.