Blue Hole, Guam

Guam's Blue Hole is one of the most celebrated cavern dives in the Pacific — a near-circular chimney in the reef crest that opens at 6 m on the surface and connects to the open ocean through a spectacular archway exit at 27 m, giving divers a cathedral of blue light and the breathtaking sensation of flying out into the Philippine Sea wall beyond. The transition from the dim interior to the sunlit open water at the arch frames schooling barracuda and grey reef sharks patrolling just outside in an almost theatrical composition. The outer wall beyond the arch drops past 300 m and hosts large pelagics year-round, making the Blue Hole both a technical cavern and a world-class wall dive in a single entry.