On 22 October 1943 "Cacapon" sailed from Norfolk, Virginia, to load fuel at Aruba in the West Indies en route to Pearl Harbor, where she arrived 12 November. On 30 November she rendezvoused with the U.S. 5th Fleet to deliver fuel at sea to the ships carrying out the Gilbert Islands operation. After a west coast overhaul, she returned to Pearl Harbor, from which she sailed 3 February 1944 to carry her vital logistic support to task force TF-50, then engaged in the Marshall Islands operation. She carried fuel on which all modern naval warfare depends to units of the U.S. 3rd Fleet from March into May, as the mighty task forces sent their strikes against Rabaul, Kavieng, Green, Emirau, and the Admiralties. During a part of this period, she served temporarily with the U.S. 7th Fleet's service support group for the New Guinea operation.