By then, the United States had entered World War II as a full partner in the Allied cause. Underway from the Boston Navy Yard on 1 May 1942, "Barnegat" transited the Cape Cod Canal later that day, anchoring for the evening in Buzzard's Bay on the Massachusetts coast. From there, she sailed to Newport, Rhode Island, and moored at the Naval Torpedo Station Newport at Newport on the morning of 2 May 1942 to take on a dozen Mark XIII aerial torpedoes before she headed on to Naval Air Station, Quonset Point, Rhode Island, where she loaded equipment and stores for Patrol Squadron 73 (VP-73). on 4 May 1942, "Barnegat" embarked the squadron's five officers and 117 enlisted men and put to sea that afternoon, bound for Iceland. Along the way, she escorted the steamer SS "Cherokee" to the Sambro Lightship and there turned over her charge to a Royal Canadian Navy escort. "Barnegat" stopped at Argentia, Newfoundland, from 7 May 1942 to 9 May 1942, and then resumed her voyage to Iceland. She arrived in Reykjavík, Iceland, late on 13 May 1942. On 14 May 1942, she moored alongside seaplane tender and unloaded VP-73's gear. On 16 May 1942, "Barnegat" arrived at the Fleet Air Base at Skagafjörður, Iceland, her base of operations for most of the next three months. There she provided not only tender services but salvage and logistic support as well. Between 20 June 1942 and 22 June 1942, she recovered gear from a Consolidated PBY-5A Catalina which had been shot down at Kossandr Beach by “friendly fire” from ships in Convoy UR 29. After an interruption to locate and salvage a barge and its valuable cargo of gasoline, she completed the task on 24 June 1942. While based at Skagafjörður, "Barnegat" also transferred aviation gasoline from tankers to a variety of ships, from Skagafjörður to Hvalfjordur, Iceland, supplying heavy cruisers and , battleship , and British aircraft carrier in that fashion. She also supplied diesel fuel to the destroyer tender . Later, on 14 August 1942, she got underway from Skagafjörður to salvage a German Focke-Wulf Fw 200 Condor reconnaissance plane that had been shot down by a United States Army fighter from Gaetta Light.