The Great Blue Hole is one of the world’s most recognisable dive sites. This almost perfectly circular marine sinkhole is more than 300 metres across and approximately 124 metres deep, creating the dark-blue centre seen in so many aerial photographs of Belize.

But the experience underwater is very different from the bright coral reef surrounding it. Divers descend into deeper, darker water to reach enormous stalactites formed thousands of years ago, when the cave was above sea level. This is a geological dive rather than a colourful reef dive, and it is the scale and atmosphere of the underwater formations that make it memorable.

The classic Blue Hole dive usually descends to around 40 metres, making it a dive for suitably qualified and experienced divers. The depth also means the time spent near the stalactites is relatively short. Good buoyancy, air awareness and close attention to the dive guide are essential.

It is possible to visit by day boat from Ambergris Caye, Caye Caulker and other parts of Belize. However, these trips require a very early start and a long boat journey across open water. A liveaboard stays around Lighthouse Reef, removing the need to make that journey from the mainland on the morning of the dive and often allowing a less rushed arrival.

And the Blue Hole is only part of the attraction. Many divers find the walls and reefs around Half Moon Caye even more impressive, with colourful sponges, healthy coral, turtles, eagle rays, reef sharks and large schools of fish. Liveaboards can offer several dives each day and night dives at suitable nearby reef sites, although night diving does not normally take place inside the Blue Hole itself.

The UNESCO Belize Barrier Reef Reserve System includes the Great Blue Hole and its surrounding protected reefs. Liveaboard.com also has a specific Blue Hole diving page, and you can compare the boats in our Belize liveaboard collection.