Blue Hole

Useful Information

Location: Northern part of the Lighthouse Reef. 11 km north of Half Moon Caye. 100 km south east of Belize City.
Open: no restrictions.
Fee: free.
Classification: KarstDoline Karstblue hole
Light: n/a
Dimension: Dia=300 m, VR=145 m.
Guided tours: diving tours by various operators
Photography: allowed
Accessibility: n/a
Address: The Reef Runner, Gilman, Stowe & Associates, P.O. Box 417912, Sacramento, CA 95841, Tel: +1-916-344-1250, Fax: +1-916-331-5026. E-mail: contact
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1972 visited by Jacques Cousteau with his ship Calypso.


The Great Blue Hole, Belize. Public Domain.
The Great Blue Hole, Belize. Public Domain.

The Blue Hole is the largest submarine sinkhole in the world. This sink hole or doline was formed by the collapse of a huge cavern.

The Blue Hole cavern formed at a time, when the water level of the worlds oceans was much deeper, about 100 m below todays sea level. This happened during the Ice Age, in the Pleistocene, when huge amounts of water were frozen and formed glaciers at the poles and all over Europe and North America. At this time the continental shelf around Middle America was above sea level and here, the limestone was heavily karstified. The cave rivers drained this plain to the sea.

At the end of the Ice Age the sea level rose, flooded the land and filled the caves with sea water. Many caves, although flooded now, are still under dry land. Others, originally closer to the sea are below flooded land, like this one. When such caverns collapse, the dolines are waterfilled. Those on land are called cenotes, a term from the indians in México. The submarine dolines have no peculiar name, as they are very rare and known for a rather short time.

Submarine dolines are of extraordinary beauty. The turquoise sea is rather shallow, but the dolines are deep, and so the water becomes dark blue. Typically the dolines are circlar and have steep walls, so the sea in this area is spotted with dark blue circles. This is best seen from an airplane.

The Blue Hole is the biggest of those submarine dolines and part of day cruises by local tour operators. It is also possible to dive into the hole and the adjoining cave, but because of the depth this is very dangerous. It is only advisable for experienced divers accompanied by a dive master.