She returned to Mare Island Naval Shipyard on 18 June 1960, and after short training cruises sailed 7 November for Pearl Harbor to join the Pacific Fleet.

During her first deployment she successfully launched her seventh consecutive Regulus I missile during a major Southeast Asia Treaty Organization weapons demonstration.

[8] Halibut entered Pearl Harbor Naval Shipyard for a major overhaul, and on 15 August was redesignated as an attack submarine with the hull classification symbol SSN-587.

Halibut then began ASW operations in the area, continuing until August 1968 when she transferred to Mare Island for overhaul and installation of: side thrusters; hangar section sea lock; anchoring winches with fore and aft mushroom anchors; saturation diving (mixed gas) habitat; long and short range side-look sonar; video and photographic equipment; Sperry UNIVAC 1224[9][10] mainframe computer; induction tapping and recording equipment; port and starboard, fore and aft seabed skids ("sneakers"); towed underwater search vehicle ("fish") and winch; and other specialized oceanographic equipment.

[citation needed] For exceptional meritorious service on support of National Research and Development efforts while serving as a unit in the Submarine Force, U.S. Pacific Fleet.

Conducting highly technical submarine operations, over an extended period of time, USS HALIBUT (SSN-587) successfully concluded several missions of significant scientific value to the Government of the United States.

The professional, military, and technical competence, and inspiring devotion to duty of HALIBUT's officers and men, reflect great credit upon themselves and the United States Naval Service.

The superb professional competence, extremely effective teamwork and exemplary devotion to duty displayed by the officers and men of USS HALIBUT reflect great credit upon themselves, the Submarine Force and the United States Naval Service.