Following trials on Lake Michigan, Mapiro entered a floating drydock at Lockport, Ill.; and was towed down the Chicago and Mississippi Rivers to New Orleans, La., to be readied for duty in the South Pacific.

She remained on observation patrol until returning to the west coast in September, arriving at San Francisco for deactivation by 25 August.

On 16 March 1946, Mapiro decommissioned to enter the Pacific Reserve Fleet at Mare Island, Calif., 1 January 1947.

The submarine was struck from the US Naval Register, and sold outright to Turkey, 1 August 1973; she was scrapped by the Turkish Navy in 1973.

In 1983, a second ex-U.S. Navy submarine, the former USS Tang (SS-563), was renamed TCG Pirireis (S-343) reusing the same hull number.