The Harbor Defenses of Manila and Subic Bays (formerly, Coast Defenses of Manila and Subic Bays) were part of the US Army's Philippine Department, prior to, and during, World War II.

In July 1941, these units were commanded by Major General George F. Moore, whose Philippine Coast Artillery Command was located at Fort Mills, on Corregidor. This command included Fort Hughes (Caballo), Fort Drum (El Fraile), and Fort Frank (Carabao); at the entrance to Manila Bay; as well as, Fort Wint (Grande Island) at the entrance to Subic Bay. At this time, there were 4,967 troops assigned to the Harbor Defenses.

Anti-Aircraft Defenses

Chief of Coast Artillery Major General Joseph A. Green had recommended reassigning elements of the Harbor Defenses to anti-aircraft duty, but this proposal was rejected. The War Department had been intending to send three additional AA regiments and two brigade headquarters, however this was not accomplished before the Japanese invasion in December of 1941.

With the exception of those areas covered by the 60th and 200th Coast Artillery (AA) Regiment, the Philippine islands were virtually defenseless against air attack.

Minefields

Manila and Subic Bays were mined by the Asiatic Fleet, stationed in Manila Bay. These minefields were designed to stop all vessels, except for submarines and shallow-draft surface craft.

See also: Military History of the Philippines