Following an availability at the Norfolk Navy Yard, the Altair reported to Commander, Operational Training Command, Atlantic Fleet, on 21 August 1943 and soon resumed active tender operations at Bermuda, this time in support of the destroyer and destroyer escort shakedown group (Task Group 23.1) until shifted to Guantánamo Bay, Cuba, where she arrived on 11 March 1945. Providing tender services at Guantánamo Bay until 3 May 1945, the Altair then returned to the Norfolk Navy Yard to be prepared for service in the Pacific theater. While the ship was on her way, Nazi Germany surrendered unconditionally and the European war ended. Prepared for "distant service", the Altair emerged from the Norfolk Navy Yard on 26 July and set course for the Pacific. Arriving in the Panama Canal Zone on 4 August, the ship remained there for the eleven days while World War II in the Pacific hastened to a conclusion with the explosion of two atomic bombs over Hiroshima and Nagasaki. The Altair sailed for Pearl Harbor on 15 August 1945. The Altair reached Pearl Harbor on 6 September 1945 and provided tender services to small ships and craft into the early spring of 1946. She departed Hawaiian waters for the last time on 27 April 1946 and reached San Francisco, California on 8 May, slated for disposal within the 12th Naval District.
