The significant battle that occurred in the Pacific Theater during World War II in 1942 was the Battle of Midway. Fought from June 4 to June 7, it was a decisive naval battle that marked a turning point in the war against Japan. U.S. forces, having broken Japanese codes, launched a surprise attack on the Japanese fleet, resulting in the sinking of four Japanese aircraft carriers—Akagi, Kaga, Soryu, and Hiryu. The battle significantly weakened the Japanese navy and shifted the balance of naval power in the Pacific towards the United States, paving the way for further Allied victories.