The contract to build Seahorse was awarded to the Electric Boat Division of General Dynamics Corporation in Groton, Connecticut, on 9 March 1965 and her keel was laid down there on 13 August 1966.

Following a shakedown cruise in the Caribbean Sea and visits to Roosevelt Roads and San Juan, Puerto Rico, and Frederiksted on St. Croix in the United States Virgin Islands, Seahorse returned to her home port, Charleston, South Carolina, joining Submarine Division 42.

For the next four months, Seahorse conducted attack submarine training, engaged in air group operations, and made final preparations for an extended Mediterranean Sea deployment.

During the months of June, July, and August 1972, she spent four weeks at sea in the Atlantic providing services for air groups and participating in destroyer operations.

Upon the outbreak of the Yom Kippur War, Seahorse got underway on less than 24-hours notice on 25 October 1973, deploying to the Eastern Mediterranean Sea with US naval and air forces monitoring the conflict and ensuring freedom of passage.

In early 1995, Seahorse departed Charleston, her home port for twenty five years, heading to Puget Sound Naval Shipyard for deactivation.

Her scrapping via the Nuclear-Powered Ship and Submarine Recycling Program at Puget Sound Naval Shipyard in Bremerton, Washington, began on 1 March 1995 and was completed on 30 September 1996.

One of her sail planes is on public display in memorial garden at the former Sand Point Naval Air Station (now Warren G. Magnuson Park) near Seattle.