"Sam Rayburn" conducted demonstration and shakedown operations on the Atlantic Missile Range, first manned by her Blue Crew and then by her Gold Crew. She joined Submarine Squadron 18 at Charleston, South Carolina, before her first Polaris ballistic missile deterrent patrol in the summer of 1965. In August 1965, she joined Submarine Squadron 16 and made seven deterrent patrols out of Rota, Spain, before rejoining Submarine Squadron 18 at Charleston in December 1966. During 1967, "Sam Rayburn" completed her 8th through 11th deterrent patrols. During 1968, she completed her 12th through 14th deterrent patrols.