Steaming via the Panama Canal, the tug arrived at San Francisco on 8 November and operated off the California coast until return to Charleston with a tow, 27 January 1946.

From June to September, she made a voyage to Iceland, and then operated out of Norfolk into 1947, departing on 6 January for Bermuda and returning after an extended tow and limited deployment on 23 March.

The fleet tug continued to operate out of Norfolk, making a number of cruises to the Caribbean and gulf coast ports until June 1948, and then departed on the 12th as escort for 11 Turkish naval vessels bound for Gibraltar via Bermuda, returning 21 July.

During the Cuban missile crisis of October‑November 1962, the ship operated on standby emergency status, towing Army personnel barges from Charleston to Port Everglades, in preparation for a possible invasion of Cuba.

Mosopelea continued on her valuable service to the Atlantic Fleet, basing out of Norfolk and performing towing, salvage, and research duties all along the east coast and in the Caribbean into 1969.