The Blue Hole in Dahab, Egypt: The Famous Red Sea Sinkhole

On the coast of Egypt's Sinai Peninsula, just north of Dahab, a nearly circular patch of deep blue water cuts into the Red Sea reef. This is the Blue Hole in Dahab, one of Egypt's best-known diving sites and one of the most recognisable underwater formations in the region. 

The Blue Hole in Dahab is a famous Red Sea sinkhole surrounded by the rugged mountains of South Sinai, Egypt.

From the shore, it can look surprisingly peaceful. The water is clear, the surrounding mountains are bare and rugged, and the Red Sea stretches out toward the horizon. Beneath the surface, however, the Blue Hole drops sharply into the reef and connects to the open sea through a submerged passage known as the Arch.

The site is part of the wider Abu Galum protected area, where coral reefs, marine life, mountains and desert landscapes meet. Egypt's official tourism site describes the Blue Hole as a 70-metre-wide, 80-metre-deep hole in the reef, while a 2026 Egyptian government report describes it as a sinkhole reaching more than 100 metres. Because published measurements vary, it is safer to describe the Blue Hole as more than 100 metres deep rather than rely on one disputed figure.

Where Is the Blue Hole in Dahab?

The Blue Hole is located near Dahab in South Sinai, Egypt, on the eastern side of the Sinai Peninsula along the Gulf of Aqaba. It lies north of Dahab and close to the Abu Galum Protectorate, a protected area known for its coral reefs, marine ecosystems, and dramatic landscape where mountains come close to the sea.

Dahab itself is around 90 kilometres north of Sharm El-Sheikh and has developed from a former Bedouin fishing settlement into one of Egypt's major diving and water-sports destinations. For travellers interested in the area, the official Experience Egypt guide to Dahab is a useful starting point for information about diving, hiking and nearby attractions.

What Is the Blue Hole?

The Blue Hole is a natural underwater sinkhole formed in the Red Sea reef. Its almost circular shape provides it with the appearance of a giant blue opening when viewed from above. The formation is not simply a deep swimming hole. The sides descend through the reef, creating an underwater environment where divers encounter steep walls, clear water, and marine life.

The surrounding Red Sea is renowned for its coral ecosystems. Egypt's tourism authorities note that the country's Red Sea waters contain hundreds of coral species and more than 1,000 species of fish, making the region particularly important for diving and snorkelling. The Blue Hole therefore attracts visitors for more than its depth. Its location combines underwater scenery with the rugged mountains and desert landscape of South Sinai.

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How Deep Is the Blue Hole in Dahab?

One of the most common questions about the site is, 'How deep is the Blue Hole in Dahab?' 

Published figures differ. Egypt's official tourism website describes the Blue Hole as approximately 80 metres deep, while a 2026 Egyptian government report describes the sinkhole as reaching more than 100 metres. 

For a general travel article, the safest description is that the Blue Hole is more than 100 metres deep, while also noting that official tourism material gives an 80-metre measurement. The important point is not just the number. The Blue Hole's steep underwater walls and the depth of its famous Arch make some dives technically demanding.

The Arch: The Blue Hole's Famous Underwater Tunnel

The feature that has given the Blue Hole in Dahab much of its reputation is the underwater Arch. The Arch is a submerged tunnel that connects the Blue Hole with the open Red Sea. It is located at considerable depth, and reaching it is very different from simply swimming or snorkelling around the upper part of the Blue Hole.

Egypt's official tourism information specifically warns that although the Blue Hole itself attracts divers of different experience levels, only highly experienced divers should attempt the route beneath the Arch. The Arch has become famous among technical divers and freedivers because of its depth, enclosed environment, and the difficulty of navigating the passage.

Why Is the Arch So Challenging?

Deep diving introduces several hazards that do not occur to the same degree in shallow water. Divers must manage depth, gas supply, decompression, and their physical and mental responses to increasing pressure. The Arch has also been associated with a number of fatal diving accidents over the years. National Geographic notes that the underwater tunnel has a history of fatalities, while also distinguishing the challenging Arch from the more accessible Blue Hole area, which is used for responsible snorkelling and diving. That distinction is important. The Blue Hole's reputation should not suggest that every visitor entering the water is attempting an extreme dive.

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Why Is the Blue Hole Considered Dangerous?

The Blue Hole became particularly notorious because of deep dives toward the Arch. At great depth, nitrogen narcosis, increased gas consumption, and disorientation can become serious concerns. A diver who misjudges depth or air consumption can find it difficult to return safely. The tunnel itself adds another complication. Unlike an open-water descent, entering a submerged passage leaves a diver with fewer direct routes back to the surface.

This is why the Arch is a site for experienced and appropriately trained technical divers rather than an ordinary recreational dive. For most visitors, there is no reason to attempt the Arch. Visitors can enjoy the scenery around the Blue Hole and its shallower reef environment without making an extreme descent.

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Marine Life Around the Blue Hole

The Blue Hole is part of a region known for rich Red Sea marine life and coral reefs. The wider Abu Galum protected area contains coral reefs, marine organisms, seagrass and other ecosystems, while its mountains and valleys support terrestrial wildlife as well.

Dahab's other dive sites also offer opportunities to see colourful reef fish, corals and other marine species. The official tourism authority lists sites such as the Lighthouse Reef, Eel Garden, The Canyon and Napoleon Reef among the area's attractions. This ecological setting is one reason conservation matters at the Blue Hole. In April 2026, Egypt announced plans to improve visitor management at the site while protecting its fragile coral reef ecosystem.

The Blue Hole and Dahab

A visit to the Blue Hole is also an opportunity to see a very different side of Egypt. Dahab sits between the Gulf of Aqaba and the mountains of Sinai. Unlike Egypt's famous archaeological destinations, the appeal here is largely natural: reefs, beaches, mountains, desert valleys and clear Red Sea water. The nearby Abu Galum Protectorate adds another layer to the experience. Visitors can combine time around the Blue Hole with hiking, snorkelling or trips farther north into the protected landscape.

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FAQs About the Blue Hole in Dahab

Where is the Blue Hole in Egypt?

The Blue Hole is near Dahab in South Sinai, on the Gulf of Aqaba coast of Egypt. It lies north of Dahab and within the wider Abu Galum protected area.

How deep is the Blue Hole in Dahab?

Published measurements vary. Egypt's tourism site describes it as about 80 metres deep, while a 2026 government report says it reaches more than 100 metres.

What is the Arch at the Blue Hole?

The Arch is a submerged tunnel connecting the Blue Hole with the open sea. It lies at significant depth and is intended for highly experienced technical divers rather than ordinary recreational divers.

Is the Blue Hole safe for snorkelling?

Snorkelers and divers visit the Blue Hole area, but you should always check conditions and access locally. The official tourism authority specifically describes snorkelling opportunities at the site while distinguishing them from the highly demanding Arch dive.

Why is the Blue Hole famous?

It is renowned for its deep blue underwater sinkhole, coral reef, the submerged Arch and its reputation as a challenging diving site near Dahab.

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Divers Cemetery

Plaques in memory of lost divers

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Dahab Blue Hole Map

The Blue Hole near Dahab is known for its deep blue water, coral reef and the famous underwater Arch.

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Conclusion

The Blue Hole in Dahab, Egypt, is one of those places where the landscape above the water is almost as striking as what lies underneath it. Rugged Sinai mountains surround a clear section of the Red Sea, while beneath the surface the reef falls away into a deep blue sinkhole.

Its most famous feature, the Arch, has made the site particularly well known among experienced divers. At the same time, the Blue Hole and the surrounding Abu Galum area are part of a much larger natural landscape filled with coral reefs and marine life.

The Blue Hole is therefore more than a famous diving challenge. It is a striking geological feature, a marine environment, and an important part of the natural attractions around Dahab. As visitor numbers and tourism continue to grow, protecting the reef and surrounding environment will be just as important as preserving the Blue Hole's reputation as one of Egypt's most unusual coastal landmarks.

References & Sources

• Experience Egypt — Blue Hole Diving
• Experience Egypt — Dahab
• Egyptian State Information Service — Abu Galum Natural Reserve
• Egyptian State Information Service — Blue Hole redevelopment and conservation, 2026
• National Geographic — Dahab and the Blue Hole