Blue hole
Great Blue Hole
A protected marine sinkhole on Lighthouse Reef where divers descend the wall to overhangs hung with ice-age stalactites. Visits are by boat with tour operators, and a daily monument fee applies.
Dive boats tie up to mooring buoys on the rim of the hole, which has no land. Divers follow the steep wall down to overhanging shelves where large stalactites hang, evidence that this was a dry cave when sea level was far lower.
The Belize Audubon Society, which publishes the monument's visitor information, lists diving, snorkelling and wildlife viewing; snorkelling takes place on the coral rim. Sharks and turtles are reported in the area.
The environment
Vertical walls and overhanging ledges with stalactites in clear marine water; deep anoxic water with hydrogen sulfide below about 90 m.
Conditions
Open marine site; trips are long boat rides from the cayes and mainland. Hydrogen sulfide and no oxygen below about 90 m (2018 survey).
Typical ranges from published sources, not current conditions.
Facilities
No land or visitor facilities at the hole; mooring buoys for dive boats. Half Moon Caye, often visited the same day, has basic visitor facilities.
For orientation, not navigation. Hollow dots are approximate.
Every fact on this page, with its source (9)
| Fact | Status | Source |
|---|---|---|
| One operator lists a maximum depth of 40 m (135 ft) for its Blue Hole dive.Provider claim. | Reported | [2] |
| The sinkhole is about 412 ft (125 m) deep. | Verified | [1] |
| A hydrogen sulfide layer at about 290 ft marks the start of oxygen-free water.December 2018 expedition. | Reported | [3] |
| One operator lists its 40 m Blue Hole depth for advanced-certified divers and requires Blue Hole divers to be at least 18.Provider claim. | Reported | [2] |
| Non-nationals pay BZD 60 per day to enter the monument.Checked 2026-10-14. | Verified | [1] |
| The monument lists hours of 8:00 am to 4:30 pm. | Verified | [1] |
| Mariners must contact Half Moon Caye park rangers (VHF 16) before mooring or anchoring. | Verified | [1] |
| There are no land or visitor facilities at the hole, only mooring buoys. | Verified | [1] |
| GeoNames lists the Great Blue Hole at 17.315278, -87.53444.Public, widely published site. | Reported | [4] |
Verified: stated by an official or primary source we opened. Reported: from a secondary source only. Sources conflict: the note gives both versions. May be out of date: the newest source we found is old.
Written in our own words from the sources above. Report a correction