Blue Hole

The Great Blue Hole of Lighthouse Reef is Belize's most famous dive site and one of the world's most recognizable underwater landmarks — a near-perfect circular karstic sinkhole 305 meters in diameter and 124 meters deep, located 60 kilometers off the coast at the heart of Lighthouse Reef Atoll. Made globally famous by Jacques-Yves Cousteau in 1971, the Blue Hole's deep blue disc is visible from space and has become a bucket-list destination for divers worldwide. The dive is a vertical wall descent inside the sinkhole, with divers dropping to 40 meters along the interior face to encounter the site's signature feature — enormous limestone stalactites hanging from overhangs at 30-42 meters, formed when the cave system was above sea level during the last Ice Age. These prehistoric formations, some reaching several meters in length, create a surreal underwater landscape that feels more like a dry cave than an ocean dive. Above the stalactites, Caribbean reef sharks and the occasional bull shark patrol the blue water of the sinkhole's interior. Marine life inside the Blue Hole is relatively sparse compared to the surrounding atoll reefs — the focus here is geological spectacle rather than biodiversity. However, the dive almost always delivers reef shark and Caribbean reef shark encounters at depth, with midnight parrotfish and groupers occasionally appearing along the wall. The shallow rim at 12 meters hosts abundant reef fish, anemones, and healthy coral cover, and the exit over the reef delivers a burst of typical Caribbean biodiversity after the deep descent. The Great Blue Hole is Advanced Open Water diving due to the 40-meter maximum depth, with strict bottom-time limits (typically 8 minutes at 40 meters) dictated by no-decompression limits. Reached exclusively by day boat from San Pedro, Caye Caulker, or Belize City (2-3 hours), or as part of Belize liveaboard itineraries. Visibility typically 30+ meters inside the hole, 20-30 meters on the surrounding reef. Water temperatures 26-29°C. Best conditions April through June.