She joined Submarine Squadron 18 at Charleston, South Carolina, before her first Polaris ballistic missile deterrent patrol in the summer of 1965.

[1] During 1969, Sam Rayburn operated continuously with Submarine Squadron 18 until commencing overhaul at Portsmouth Naval Shipyard at Kittery, Maine, in December 1969.

[citation needed] Sam Rayburn was decommissioned on 31 July 1989 and reclassified a moored training ship (MTS) with hull number MTS-635.

[3][4] Struck from the Naval Vessel Register on 31 July 1989,[5] she arrived at the Naval Nuclear Prototype Training Unit at Goose Creek, South Carolina, in August 1989 after achieving initial criticality in her new role on 29 July 1989.

MTS-635 departed the Naval Nuclear Power Training Unit Charleston on 1 April 2021 via a tow vessel and escort, arriving at Norfolk Naval Shipyard in Portsmouth Virginia on 3 April 2021 to await defueling and eventual dismantling.