The Great Blue Hole is a 410 ft deep marine sinkhole near the center of Lighthouse Reef, Belize, about 45 miles east of Caye Caulker. Fly over it to see the full circle, or spend a day on a boat trip to dive among the stalactites or snorkel the reef around the rim.
Every photo of the perfect navy circle is taken from the air. Certified deep divers see the stalactites at about 130 ft, snorkelers see the coral on the rim, and only scenic-flight passengers see the shape. Pick what you want to see, then pick how to go.
The whole circle from the air, with the barrier reef and Turneffe Atoll on the way out. No swimming.
One dive inside the hole to about 130 ft, then two reef dives. How deep you can go depends on your certification and logged dives.
Diving the Blue Hole
Along the shallow coral rim, looking down the wall rather than into the deep interior. Then Half Moon Caye and the Aquarium.
Not getting in the water? Some operators may take ride-along passengers, so ask when you book. A scenic flight is the dry way to see the circle.
Boat trips leave from Caye Caulker, San Pedro and Belize City. Prices are per person from Caye Caulker operators, checked November 2026.1
A boat trip to the Great Blue Hole takes a full day: an early start, 2-2.5 hours of open water each way and three stops on the atoll. A scenic flight takes about an hour and leaves the rest of your day free. Most Caye Caulker operators follow the order below, but the second and third stops vary by operator.
Caye Caulker operators meet between 5:00 and 5:30 am, depending on the operator. Two of the three serve breakfast on board.
Open water the whole way, passing Turneffe Atoll.
The deep dive, or a snorkel along the rim.
Lunch on the island, the red-footed booby colony, then a wall dive or snorkel.
A shallow last stop off Long Caye before the ride back.
A patch of darker blue in the reef. At sea level the circle is hard to make out.
Divers cleared for deep dives reach the stalactites at about 130 ft. Snorkelers see coral and reef fish on the shallow rim.
The full navy circle, the ring of reef around it and the atoll's lagoon.
Every visit to the Great Blue Hole is a tour: a dive or snorkel boat, or a scenic flight. There is no way to go out on your own.
Boats leave from Caye Caulker, San Pedro on Ambergris Caye and Belize City, and the crossing takes 2-2.5 hours from each. On Caye Caulker, three operators run the trip. Some operators only sail once 10 to 12 people have booked.1
Scenic flights go from Caye Caulker, San Pedro and Belize City. Shared flights sell seats on set days, not daily, and a Caye Caulker tour operator charters five-seat planes. The flights circle the hole and return without landing.1 Compare prices and departure days on our Great Blue Hole tours page.
The Great Blue Hole sits at 17.315° N, 87.534° W and has been protected as the Blue Hole Natural Monument since 1999. It is one of seven sites in the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site since 1996.2, 3
| Leaving from | Straight-line distance | By boat | Scenic flights |
|---|---|---|---|
| Caye Caulker | 45 mi (72 km) | 2-2.5 hours | Yes |
| San Pedro (Ambergris Caye) | 50 mi (81 km) | 2-2.5 hours | Yes |
| Belize City | 45 mi (72 km) | 2-2.5 hours | Yes |
Lighthouse Reef from orbit. The Blue Hole is the dark circle near the top.
Simplified map; positions are approximate and the route is indicative.
The Great Blue Hole is about 410 feet (125 m) deep and 1,050 feet (320 m) across, based on a 2013 seismic survey published in Marine Geology.4 Other published figures sit between 120 and 125 m (394 to 410 ft), depending on the survey and how it was measured.
| Source | Depth | Width | Year |
|---|---|---|---|
| Gischler, Anselmetti & Shinn (seismic survey) | 410 ft (125 m) | 1,050 ft (320 m) | 2013 |
| Jones & Dill (cited by Wikipedia) | 407 ft (124 m) | 1,043 ft (318 m) | 2002 |
| CNN report on the Aquatica submarine expedition | About 410 ft (125 m) | 984 ft (300 m) | 2019 |
The Great Blue Hole is famous, but it is not the deepest blue hole. Taam Ja' in Chetumal Bay, Mexico, is at least 1,380 ft (420 m) deep, and its bottom has not been reached yet.5 Dragon Hole in the South China Sea measures 987 ft (301 m).6 Both are more than twice as deep as the Great Blue Hole.
Dive trips go to about 130 feet (40 m), roughly a third of the way down.7
The Great Blue Hole began as a limestone cave on dry land. During the ice ages, sea level sat far lower than today. The rock dissolved into a cavern, its roof collapsed, and when the ice sheets melted the rising sea flooded the hole.4
The stalactites are the proof. They only grow from water dripping in air, so the ones divers swim past at about 130 ft formed before the sea came in. A giant stalactite that Jacques Cousteau's team brought up in 1970 has a freshwater core that grew roughly 20,000 to 12,000 years ago, wrapped in a marine crust that built up after the sea flooded the cave in the last 11,000 years or so.8
The Great Blue Hole is mainly a geology dive: marine life inside the hole is sparse, with sharks or rays an occasional sight around the rim. UNESCO lists great hammerhead sharks among the Blue Hole's wildlife.3 Below a layer of hydrogen sulfide at about 300 ft (90 m), the water has no oxygen and nothing lives there.9
Half Moon Caye, the lunch stop on Caye Caulker's Blue Hole trips, has a large red-footed booby colony.3 It has been protected as a Natural Monument since 1982 and, like the Blue Hole, is co-managed by the Belize Audubon Society.2 The Half Moon Caye Wall dive is where reef sharks, eagle rays and turtles turn up.
Blue Hole boat days from Caye Caulker usually stop at Half Moon Caye and the Aquarium at Long Caye, though the exact stops vary by operator. You pass Turneffe Atoll on the way, but diving there is a separate trip.
Lunch stop, booby colony and a wall dive just offshore.
Shallow reef stop for the last snorkel or dive of the day.
You cross it on the way out. Diving or snorkeling there is its own day trip.
In late 2018, two submarines made more than 20 dives into the Great Blue Hole and mapped its inside with sonar. Around 300 ft down they passed through the hazy hydrogen sulfide layer, and at about 350 ft they found a graveyard of conchs and other shellfish that had strayed too deep.9 The crews also found the remains of two divers lost in the hole, and left them undisturbed.10
The floor of the Great Blue Hole is also a storm record. Researchers drilled a 100 ft (30 m) sediment core from the bottom, and its layers hold a 5,700-year history of tropical storms and hurricanes. The record shows storms in the region becoming steadily more frequent.11
The Great Blue Hole is in the Caribbean Sea off Belize, near the center of Lighthouse Reef atoll, about 45 miles (72 km) in a straight line from both Caye Caulker and Belize City. It is protected as the Blue Hole Natural Monument, part of the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site.
You can visit the Great Blue Hole without diving by taking a scenic flight over it or a snorkel trip to the rim. A flight is the only way to see the whole circle.
The Great Blue Hole is worth it for certified divers who want to see the stalactites at about 130 ft, and for anyone who wants the aerial view from a scenic flight. If you mainly want fish and coral, the reef stops at Half Moon Caye and the Aquarium on the same trip have more marine life than the hole itself.
You can swim in the Great Blue Hole on a snorkel trip, which stays in the shallow water over the coral rim. The deep interior is only visited by certified divers on a guided dive.
The Great Blue Hole is not the deepest blue hole in the world. Taam Ja' in Mexico is at least 1,380 ft (420 m) deep and Dragon Hole in the South China Sea is 987 ft (301 m). At 410 ft, the Great Blue Hole is better known for its near-perfect circle and its stalactites.
The Great Blue Hole is not the same place as St. Herman's Blue Hole, which is an inland swimming hole in a national park near Belmopan on the mainland.