For the Japanese, maintaining control of the Philippines was essential because their loss would enable the Allies to sever their oil supply lines from Borneo and Sumatra.

However, this was not at first clear, and the Japanese commander in the Philippines, General Tomoyuki Yamashita, believed that the United States Navy had suffered severe casualties and that the Allied land forces might be vulnerable.

Accordingly, he began to reinforce and resupply the garrisons on Leyte; over the course of the battle the Japanese ran nine convoys to the island, landing around 34,000 troops from the 1st, 8th, 26th, 30th, and 102nd divisions.

Decryption of messages sent using the PURPLE cipher alerted the Allies to the concentration of Japanese shipping around Leyte, but they initially interpreted this as an evacuation.

[2] Bad weather in late November made air interdiction less effective, and the U.S. Navy began to send destroyers into Ormoc Bay.

[5]: 176–177 An Allied patrol plane radioed a message to the division noting that a surfaced Japanese submarine (I-46) was south of Pacijan Island and heading for Ormoc Bay.

[5]: 179 The U.S. ships sank the transports as they were unloading but came under heavy attack from Yokosuka P1Y "Frances" bombers, shore batteries, submarines that were known to be in the harbor, and the Japanese destroyers.

[8] On 7 December, the 77th Infantry Division, commanded by Major General Andrew D. Bruce, made an amphibious landing at Albuera, 3.5 mi (5.6 km) south of Ormoc City.

The 77th Division's 305th, 306th, and 307th Infantry Regiments came ashore unopposed, but naval shipping was subjected to kamikaze attacks, resulting in the loss of destroyers Ward and Mahan.

[9] Convoy TA-9 landed some 4,000 troops at Palompon, but escorting destroyers entered the bay on 11 December where two, Yūzuki (by air attacks) and Uzuki (by PT boats), were sunk and the third, Kiri, was damaged.

[2] By fighting this series of engagements in Ormoc Bay, the U.S. Navy was eventually able to prevent the Japanese from further resupplying and reinforcing their troops on Leyte, contributing significantly to the victory in the land battle.