After the Japanese attack upon the Pacific Fleet at Pearl Harbor brought the United States into World War II, the "Altair" maintained a routine of carrying out upkeep and repairs on Atlantic Fleet destroyers at Bermuda that continued into the summer of 1942. Underway for San Juan, Puerto Rico, on 3 July 1942, escorted by the destroyers and , the "Altair" arrived at her destination on the 6th, detaching the two destroyers and picking up another, the , which escorted the tender to Trinidad, where she arrived on 11 July. Except for brief periods at Aruba and Curaçao, in the Dutch West Indies, in early September, the "Altair" tended destroyers at Trinidad through mid-July 1943.