Subic Bay is a bay on the west coast of the island of Luzon in the Philippines, about 100km northwest of Manila Bay. Formerly the site of a major United States Navy base, it is now the location of an industrial and commercial area known as the Subic Bay Freeport Zone under the Subic Bay Metropolitan Authority.

Subic Bay is surrounded by Olongapo City, the town of Subic and the Subic Bay Freeport Zone, both in the province of Zambales. Also in the bay was Cubi Point Naval Air Station and Grande Island, once home to Fort Wint and later turned into a military resort. Development of Olongapo City was largely tied to the presence of the United States Navy base at Subic Bay, once the largest U.S. military base in Asia. An arsenal and ship-repair facility was established at Subic Bay in 1885 by the then colonial power, Spain. Following the Spanish-American war of 1898–1899, Subic Bay became a U.S. Navy and Marine base, and grew to be a major facility.

In 1991, the Philippine Senate rejected terms for renewal of the lease of the base. After nearby Mount Pinatubo erupted, the base closed and the last ships left in 1992. The residents of nearby Olongapo City that hosted US Naval military presence for 94 years under the leadership of their mayor, Richard J. Gordon, some 8,000 people volunteered to protect and preserve for posterity the US $8 Billion worth of facilities and property from looting and destruction.

Subic has since been transformed and became a model for bases conversion into commercial use after the Cold War with blue chip companies pumping in over $3 billion of investments creating 70,000 jobs in the first four years. It was host to the 4th APEC Leaders' Summit in November 24, 1996. Federal Express's Asia Pacific hub, Asia-One, is at Subic Bay.

In addition to commercial use, Subic Bay is also a popular destination for weekend visitors from Manila. Attractions include several small beaches, an underwater aquarium, jungle survival tours, and duty-free shopping centers