The Battle of the Philippine Sea was a major naval battle of World War II on 19–20 June 1944 that eliminated the Imperial Japanese Navy's ability to conduct large-scale carrier actions. It took place during the United States' amphibious invasion of the Mariana Islands during the Pacific War. The battle was the last of five major "carrier-versus-carrier" engagements between American and Japanese naval forces, and pitted elements of the United States Navy's Fifth Fleet against ships and aircraft of the Imperial Japanese Navy's Mobile Fleet and nearby island garrisons. This was the largest carrier-to-carrier battle in history, involving 24 aircraft carriers, deploying roughly 1,350 carrier-based aircraft.

The Mariana and Palau Islands campaign, also known as Campaign Plan Granite II, was an offensive launched by United States forces against Imperial Japanese forces in the Pacific Ocean between June and November 1944 during the Pacific War. The campaign consisted of Operation Forager, which captured the Mariana Islands, and Operation Statemate, which captured Palau. Operation Causeway, the invasion of Taiwan was also planned but not executed. The offensive, under the overall command of Chester W. Nimitz, followed the Gilbert and Marshall Islands campaign and was intended to neutralize Japanese bases in the central Pacific, support the Allied drive to retake the Philippines, and provide bases for a strategic bombing campaign against Japan.