The Most Spectacular Blue Holes in the World
5 places in 4 countries · updated 14 October 2026
In short: By our ranking, the most spectacular blue holes in the world are Great Blue Hole (Belize), Blue Hole (Egypt) and Dean's Blue Hole (The Bahamas). The list covers 5 blue holes in 4 countries. The United States has the most, with 2. Last updated 14 October 2026.
A blue hole is a sudden depth in shallow water: a near-perfect circle of dark blue set into the turquoise of a reef or lagoon. Most formed during ice ages, when sea level was much lower and rain dissolved vertical caves into exposed limestone; as the sea rose again the caves flooded, leaving shafts that drop far below the surrounding seabed. Their power comes from that contrast of colour and that sense of a void opening underfoot, best seen from the air or felt by a diver hanging over the edge.
The collection includes both marine and inland examples. The Great Blue Hole off Belize is a vast round sinkhole in the middle of Lighthouse Reef, made famous by Jacques Cousteau. Dean's Blue Hole on Long Island in the Bahamas plunges from a sheltered beach cove to a depth of about 200 metres, one of the deepest known. On Egypt's Red Sea coast near Dahab, the Blue Hole opens right beside the shore. Texas has two inland variants: Jacob's Well, an artesian spring that drops into a flooded cave, and Hamilton Pool, a green swimming hole beneath a collapsed limestone grotto with a waterfall pouring over its rim.
Every blue hole here was chosen for how it looks and the list is ordered by beauty. Each has its own description, a photograph credited to its author and a place on the map, and the section also opens country by country on separate pages.
In this list
| # | Place | Type | Country | UNESCO |
|---|---|---|---|---|
| 1 | Great Blue Hole | Blue hole | Belize | ✓ |
| 2 | Blue Hole | Blue hole | Egypt | |
| 3 | Dean's Blue Hole | Blue hole | The Bahamas | |
| 4 | Jacob's Well (Texas) | Blue hole | United States | |
| 5 | Hamilton Pool Preserve | Blue hole | United States |
01 Great Blue Hole
Belize17.316° N 87.534° W
- UNESCO World Heritage
- UNESCO natural beauty
The TerraMar Project · CC BY 2.0 The Great Blue Hole is a near-perfect circle of deep indigo set in the pale turquoise of Lighthouse Reef, an atoll some 70 kilometres off the coast of Belize. Seen from the air it looks unreal: a ring of coral about 318 metres across, with the water inside dropping away to around 124 metres. It is the centrepiece of the Blue Hole Natural Monument and part of the Belize Barrier Reef Reserve System, a UNESCO World Heritage Site.
Did you know? A 30-metre sediment core drilled from its floor records 574 storms over 5,700 years, showing tropical cyclones becoming more frequent in recent decades.
02 Blue Hole
Egypt28.572° N 34.537° E
S. Ellermann · CC BY-SA 3.0 A few kilometres north of Dahab, on the Sinai coast of the Gulf of Aqaba, the fringing reef opens into a near-circular shaft of dark blue water. The Blue Hole is a submarine sinkhole more than 100 metres deep, cut off from the open sea on the surface by a shallow lip of reef about 6 metres down, known as the Saddle. Deeper down, a tunnel called the Arch links the hole with the outer reef wall: its ceiling lies at about 55 metres, it runs for about 26 metres, and on the seaward side the seabed plunges to more than 1,000 metres. The walls are covered in hard and soft coral and crowded with reef fish, and because the hole is entered straight from the shore with little current, it is one of the best-known freediving sites in the world.
Did you know? Trained freedivers swim through the Arch on a single breath, passing beneath a rock ceiling that lies about 55 metres below the surface.
03 Dean's Blue Hole
The Bahamas23.106° N 75.009° W
Ton Engwirda · CC BY-SA 3.0 nl On the coast of Long Island in the southern Bahamas, a small crescent of white sand curls around a patch of sea that suddenly turns from pale turquoise to ink. That dark disc is Dean's Blue Hole, a vertical shaft in the limestone that drops to about 202 metres — the third-deepest blue hole known in the world. At the surface the opening is only some 30 metres across, but below the water the cavity widens into a chamber roughly 100 metres wide, so that a swimmer floating over the rim is hanging above a vast hidden room.
Did you know? Only two blue holes are known to be deeper: Taam Ja' in Mexico's Chetumal Bay and the Dragon Hole in the South China Sea.
04 Jacob's Well (Texas)
United States · 24.5 km from San Marcos30.034° N 98.126° W
Larry D. Moore · CC BY 4.0 Jacob's Well looks like nothing more than a round blue pool at the bottom of Cypress Creek — a 12-foot-wide opening in the limestone that people have swum in for generations. What's underneath is the real attraction and the real danger: a flooded cave system with one passage running roughly 1,370 meters back from the surface and a second branch about 300 meters long, both cut through narrow, disorienting limestone in water that holds close to 20°C year-round.
Did you know? In 1924 the spring gushed with such artesian pressure that its water rose about 6 feet into the air above the creek.
05 Hamilton Pool Preserve
United States · 37.7 km from Austin30.342° N 98.127° W
Image by ravik777 from Pixabay A jade-green pool lies beneath a half-collapsed limestone dome, and from the lip of the overhang a waterfall about 50 feet (15 m) high drops straight into it. Hamilton Pool, in the Texas Hill Country west of Austin, formed thousands of years ago when erosion brought down the roof of a grotto carved by an underground river, leaving a natural bowl walled by cliffs and half-roofed by a great arching ledge.
Did you know? Traces of human culture found around the canyon date back more than 8,000 years, drawn by its water, shelter and rich plant life.
How this list is ranked
Places are chosen for how they look, not for how famous they are: each one has its own description and a photograph credited to its author. The order is a single world ranking that weighs the beauty of the place in curated photography together with how widely it is documented — the number of language editions of its encyclopedia article and how often that article is read in a year. The list is rebuilt as places are added, so the order and the counts on this page are always current.
Questions people ask
- What is a blue hole?
- A blue hole is a large vertical cave or sinkhole, open to the surface, that has been flooded by the sea or by groundwater. Its depth makes it look dark blue compared with the shallow water around it.
- What is the most spectacular blue hole in the world?
- On our list, Great Blue Hole (Belize) ranks first, followed by Blue Hole (Egypt) and Dean's Blue Hole (The Bahamas).
- Which country has the most blue holes?
- In our collection, the most come from the United States (2), Belize (1) and Egypt (1).
- How was the Great Blue Hole in Belize formed?
- It began as a limestone cave system on land during the last ice age, when sea level was much lower. As the ice melted and the sea rose, the cave roof collapsed and the cavity flooded, leaving a round sinkhole about 300 metres across in Lighthouse Reef.
- How many blue holes are on this list in the world?
- The list covers 5 blue holes in 4 countries. The United States has the most, with 2.