Subic Bay holds one of the highest concentrations of accessible 20th-century shipwrecks in Southeast Asia, the result of three separate naval conflicts in the same body of water. Most wrecks lie between 18 and 40 metres, and the bay's relatively calm and shallow water keeps visibility usable year-round.
A handful of dive shops in the freeport — Boardwalk Divers, Johan's Beach, and Arizona — run daily wreck dives and certification courses. The most popular dive is the San Quintin, the Spanish cruiser sunk in the Battle of Manila Bay in 1898 and the only Spanish-American War wreck divers can visit anywhere in the world.