The pivotal battle in the Pacific Theatre that marked a turning point for the U.S. against Japan was the Battle of Midway, fought from June 4 to June 7, 1942. This key naval battle occurred just six months after Japan's attack on Pearl Harbor. American forces, having successfully decoded Japanese plans, ambushed a significant portion of Japan’s carrier fleet, sinking four Japanese aircraft carriers and establishing naval dominance in the Pacific. This victory drastically shifted the momentum of the war in favor of the Allies and began a series of successful offensives leading closer to Japan’s mainland.