"Haggard" joined 5th Fleet at Eniwetok 21 May to prepare for the Marianas operation, as America's amphibious might pressed across the Pacific. Departing Eniwetok 8 July, "Haggard" arrived Guam with battleships "Pennsylvania" (BB-38) and "New Mexico" (BB-40) and other fleet units 17 July and began a bombardment of the beach fortifications. With the landing on Guam of Marines 21 July, the destroyer turned to close fire support, lending her gunfire to the battle ashore.