At Pearl Harbor again in January 1965, Plunger was selected to demonstrate the capability of the Navy's latest ASW weapon system to Dr. Donald Hornig, Special Assistant to the President for Science and Technology.

During this deployment, Plunger conducted evaluation exercises of the AN/BQQ-1 sonar systems and traveled as far east as Okinawa and Subic Bay.

"Plunger" was also the successful test bed for a new torpedo tube launched rocket called the "SubRoc" which was used in anti-submarine operations at a distance of up to twenty-five miles.

Commander Alvin L. Wilderman, the submarine's skipper, was washed overboard from the bridge in a storm near San Francisco on 30 November 1973.

She was involved in a collision with a freighter off Southern California while coming to periscope depth in early 1985 which damaged portions of her bow and sonar dome.

During the 1986 WestPac Plunger participated in naval exercises with ships from the US, Japan, and other nations as well as a ten-week "special operation", for which it was awarded the Meritorious Unit Commendation.

Plunger made her final WestPac deployment in 1988, visiting Japan and the Philippines as well as Guam and Chinhae, South Korea (and making port calls in Okinawa and Hong Kong) and conducting another two-month "special operation" that garnered her a Navy Unit Commendation.

Ex-Plunger entered the Nuclear Powered Ship and Submarine Recycling Program in Bremerton, Washington, on 5 January 1995 and on 8 March 1996 ceased to exist.

And as of its retirement Plunger was the only submarine to win the Arleigh Burke Award (in 1969 under Commanding Officer Nils Thunman).