The United States had approximately 146,000 troops in the Philippines, primarily composed of Philippine locals. The impending war was evident to all, prompting General MacArthur, the military advisor to the Philippine Government, to assume direct command of the army.

The Japanese had planned to bomb the Philippines simultaneously with their attack on Pearl Harbor, but adverse weather conditions postponed the operation. Initially, American aircraft in the Philippines were prepared for an attack and had even taken to the air to avoid being detected on the ground. However, when the attack materialized around noon on December 8th, the majority of the American planes were grounded for refueling and preparing to assault Taiwan. Consequently, the Japanese managed to eliminate a significant portion of the American ground forces.

On December 8th, the first Japanese troops commenced their landing operations on Bataan Island. American aircraft responded by attacking the landing troops, inflicting damage on four attempts and sinking a minesweeper. Nevertheless, these efforts proved ineffective. On December 12th, the Japanese landed approximately 2,500 men in southern Luzon. Additionally, they launched an attack on the American naval base at Cavite, compelling the navy to withdraw all of its non-submarine vessels from the Philippines.

On December 22nd, the primary Japanese landing occurred on the eastern coast of Lingayen Gulf. US forces were unable to halt the invasion. By evening, Japanese troops had advanced ten miles into the island. The following day, Japanese troops landed along the shore of Lamon Bay in southern Luzon. Manila proved undefendable according to the plan for withdrawal in the Bataan Peninsula. Over 80,000 troops and 20,000 refugees managed to withdraw. The initial Japanese attacks on the area were repelled by American forces. American and Philippine forces successfully held off the Japanese on the peninsula for all of January and February, and most of March. In mid-March, General MacArthur was ordered to withdraw to Australia. However, new Japanese forces arrived, and on April 3rd, Japanese troops breached the defenses. On April 10th, the last American forces surrendered.

This left the forces on the island of Corregidor. There were 11,000 army personnel on the island, including extensive tunnels that could not be destroyed by the relentless Japanese air and artillery attacks. The Japanese landed forces on Corregidor on May 5th. On May 6th, General Wainwright requested terms of surrender. The Japanese commander demanded the surrender of all US troops in the Philippines. Wainwright agreed, and the Philippines surrendered on May 8th.