After brief shakedown off the coast of Southern California, Grand Canyon departed Port Townsend, Washington on 26 June 1946 en route to Newport, Rhode Island via the Panama Canal Zone.

Assigned the task of keeping United States Navy destroyers in operation, Grand Canyon cleared Newport on 17 September 1946 for her first tour with the 6th Fleet in the Mediterranean Sea.

During this period the Grand Canyon, as flagship, took part in fleet exercises and visited the ports of Augusta, Messina and Taranto.

After visits to Tromsø, Norway and the Isle of Portland, England Grand Canyon once again returned to Newport, arriving on 21 October.

Grand Canyon continued her tender duties out of Fall River until 1 August 1958 when she sailed for Souda Bay on the Island of Crete to support the 6th Fleet in operations off Lebanon.

Besides Souda Bay, Grand Canyon visited Izmir, Turkey, Athens, Greece, Naples, Italy and Barcelona, Spain before returning home in December.

She proceeded to San Juan, Puerto Rico, arriving 3 November 1962 to start tending ships of the South Atlantic Blockading Fleet during the Cuban Missile Crisis and subsequent quarantine.

With the completion of modernization on 3 January 1964, Grand Canyon sailed for Guantanamo Bay and San Juan on training cruises.