The Most Dangerous Underwater Caves in the World

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Beware: You should never explore wild caves alone or without proper gear. Consider getting in touch with a Grotto of the National Speleological Society at or a qualified cave club. These groups are skilled and will train you. Without sufficient knowledge, preparation, and equipment, cave exploring can lead to serious injury or death.

Something about extreme sports attracts people, even knowing the risks involved. When it comes to caving, which is definitely an extreme sport, some opt to go exploring in the most remote locations, even dangerous underwater caves where there are no payoffs.

Many divers have unfortunately not returned from these trips, and yet more people continue to seek the adventure associated with some of these sites.

Because of the challenges of diving in a submerged cave system, cave diving certification requires substantial training. Even then, it is not without risk. Professionals received injuries or worse after an unfortunate incident at a location they’d visited many times before.

Cave divers are people who willingly place themselves in dangerous situations to test their boundaries. Either in the name of research, adventure, or sport, these brave individuals undergo rigorous training and take every precaution to ensure a safe trip. Still, despite their best efforts and advancements of contemporary technology, dozens of divers drown every year in the depths of underwater caves. Not every body is recovered, either.

Listed below are some of the world’s most dangerous underwater caves. We strongly urge you not to go exploring at any of these sites yourself.

Cenote Esqueleto, Mexico

One of the world’s most dangerous underwater caves is the Cenote Esqueleto in Cancun, Mexico. Several films and documentaries have shown the enormous cave system beneath the ocean’s surface. Furthermore, it is risky because entering the cave requires a tremendous 30-foot (9 meters) drop into the waters.

In addition, there is no natural light in the vast cave system, which extends underground indefinitely. Although it can get very gloomy underwater, divers ought to remain cautious and stay in regions with sunlight.

Divers become disoriented and lost because of the mix of the complex tunnels and the dark corridors. On average, three people yearly lose their lives at this dive location because of various complications. As a result, most divers stay in the open water where it is safe.

Learn about more cenotes found in Mexico here.

An image shows a diver swimming through the waters of Cenote Esqueleto, one of the most dangerous caves.

Devil’s Caves, Ginnie Springs, Florida

Located just off the coast of Gainesville, Florida, the Devil’s Caves system at Ginnie Springs is one of the most treacherous cave systems on the planet. The system’s three individual springs are Little Devil, Devil’s Ear, and Devil’s Eye.

As the name suggests, Devil’s Ear is a canyon-like passageway, found between the Santa Fe River and Devil Spring. At the Devil Spring’s base is a cylindrical limestone shaft known as the Devil’s Eye Spring. Certified cave divers frequent Devil’s Spring more than any other cave.

Although they share similarities, each has difficulties that should not be taken lightly. Imagine narrow channels and areas of varying waters that function like currents that could cause harm to diving gear.

A tight “no-lights” restriction is in effect today, and only trained cave and cavern divers are permitted to access the caverns with illumination devices.

An image shows the walkway leading down to Devil's Den, one of the more dangerous underwater caves in Florida.

Diepolder Cave System, Florida

Located on the Sand Hill Boy Scout Reserve, the Diepolder Cave Systems include the massive Diepolder II and Diepolder III caverns.

Whereas Diepolder II is the deepest at over 110 meters (360 feet), Diepolder III comes in at a close second at around 90 meters (300 feet). The Florida Speleological Society strictly regulates entry due to the cave system’s high depths and intricacy.

Any scuba diver planning on exploring these caverns should be a licensed Complete Cave Diver who has completed at least 100 cave dives in five distinct cave systems.

Trimix certification is also essential for divers. A guided program has been set up to protect divers’ safety and reduce the harmful impact on the cave systems, as this is a state-managed and privately-owned facility.

Blue Hole, Gulf Of Aqaba, Egypt

Off the Egyptian coast, there is a mysterious blue hole in the middle of the Gulf of Aqaba. The “Diver’s Cemetery” is not called that for nothing; some call it the most dangerous scuba site on earth.

40 divers have perished at this site in the past decade, but some believe this number is severely underestimating reality. Some estimate upwards of 130-200 deaths have occurred here, only in recent years.

One of its most recognizable features is “the arch,” a winding entrance to deeper waters that begins around 183 feet (56 meters) below ground.

Did you know that a scuba diver shouldn’t go deeper than 100 feet (30 meters)? You shouldn’t venture into this “hole cave” even if they pay you. Nitrogen narcosis can impair a diver’s ability to think clearly and act swiftly if they descend to such depths.

Not only that, but it might also lead to confusion and passing out. The arch, the deepest part of the Hole, leads to a reef tunnel 85 feet (26 meters) long that plunges 170 (52 meters) feet into the open sea. If divers are affected by nitrogen narcosis and fail to notice the opening of the ‘arch,’ they will likely perish at great depths.

An image shows the location of the Blue Hole in the Gulf of Aqaba, Egypt, where many divers have perished.

Florida’s Eagle’s Nest Sinkhole

Eagle’s Nest, a typical pond in the Chassahowitzka Wildlife Management Area, is considered by some to be the “Mount Everest” of cave diving. Even so, divers can go down into a sinkhole that leads to a network of large underwater tubes that go as deep as 300 feet (90 meters).

The “chimney” down into the Nest leads to a vast cavern known as the “Main Ballroom,” which branches off many tunnels and crannies leading further into the Nest. Eagle’s Nest, widely considered among the world’s most dangerous dives, has taken the lives of over a dozen divers who were overconfident in their skills.

Several factors led to these accidents, including the absence of a continuous guideline, reduced visibility due to stirred-up dirt, broken machinery, and insufficient fuel reserves for the climb.

Currently, every diver must register online and sign a liability waiver before they can dive.

An image shows a diver swimming through Florida's Eagle's Nest Sinkhole, and a sign warns them to not go further, as this is one of the most dangerous underwater caves and offers no rewards.

Mount Gambier, Australia: The Shaft Sinkhole

As volcanoes rocked the earth over 5,000 years ago, a unique region formed at the limestone foundation of Mount Gambier in south Australia.

Lava caves, an array of cenotes, breathtaking lakes, and more are found here today. You can do a lot of cave diving at this amazing dive spot. However, the sinkhole in the shaft is the world’s most dangerous cave dive. Getting through the manhole at the start of the dive requires the diver to disrobe because there isn’t enough room for both them and their gear.

After all their gear has been checked in, they can begin their dive into a network of caves that are pitch black and highly dangerous. During this dive, conserving oxygen is crucial if divers need help or remember to bring enough for the ascent. Several divers have tragically perished for this very reason.

One of these cenotes is shown below, but the sinkhole is nowhere near this tranquil.

An image shows a scuba diver getting ready to enter the cenote at Mount Gambier.

Coco’s Island, Costa Rica

Coco’s island is one of the world’s most isolated dive spots. Situated around 340 miles (548 km) off the Pacific coast, this destination may be reached by boat in a little over 35 hours.

Still, the abundance of sharks in the area makes this dive spot risky. White-tip reef sharks, enormous manta rays, hammerhead sharks, dolphins, and sea turtles are some common marine life that may be seen here.

A pair of divers spots a massive whale and schools of fish by one of the the dangerous underwater caves of Coco's Island in Costa Rica.

Samaesan Hole, Samaesan Bay, Thailand

Samaesan Hole, located in Thailand’s Samaesan Bay, is undoubtedly unique when it comes to dangerous underwater caves. Can you picture yourself scuba diving into a cave full of innumerable bombs? This is because the pit used to serve as a military dump. There are loads of unexploded bullets, bombs, and other discarded items scattered about.

In addition to this, the Samaesan Hole is dangerous because it goes down 279 feet (85 meters) into the ground. If scuba divers enter the cave unprepared, they risk being swept away by its powerful currents.

These currents are strong enough to pull a diver down like something out of a horror movie. At this depth, sunlight has difficulty reaching the bottom. Thus, divers don’t only need the appropriate technical training. Without appropriate gear, they will risk getting disoriented and lost, and a rescue that wasn’t prepared in advance would be a miracle.

Jacob’s Well, Wimberley Texas

Southwest of Austin, Texas, there is a swimming hole known as Jacob’s Well. Nevertheless, going beneath the surface, you’ll find a completely new and exciting world.

The first two chambers of Jacob’s Well are accessible to most divers, while the third chamber presents some challenges. This chamber comprises twisting, turning passageways, and the cave floor is littered with potentially dangerous pebbles and silt.

As these tiny particles are disturbed, visibility drops rapidly, leading divers to get disoriented, fear, and use up their air supply considerably more quickly than usual. Eight unfortunate souls have already met their end in these dreary confines.

An image shows Jacob's Well at the surface, which leads to several chambers of diving adventure.

Orda Cave, Russia

The western Ural Mountains conceal the gypsum crystal cave of Orda. With over 15,000 feet (4,600 meters) in length, it is one of the longest underwater caves you will ever find.

As a result of the gypsum rocks, the water is wonderfully clean but also very cold, with an average temperature of just 4 °C (40 °F).

The mysterious landscape has inspired tales of supernatural beings, such as “The Lady of the Cave,” who appears as a beautiful young woman dressed in white. Divers who enter the Orda cave have reported feeling safe and guided by her presence.

No one can count on The Lady of the cave’s protection forever, though. Orda is one of the world’s most treacherous cave dives due to its frigid waters, jagged walls, and winding channels. Scores of divers have perished trying to navigate it.

Divers at the Orda Cave Underwater Speleology Center are expected to submit a dive request and present documentation of their diving qualifications before diving.

A diver swims through Orda's Cave in Russia, one of the most dangerous underwater caves.

Devil’s Hole, Nevada, USA

Devil’s Hole is a currently closed-off underwater cavern located near Death Valley in Nevada. While some have taken the chance to explore, at least a few have perished in the process.

This cave is unique because it features an endangered species, the Devil’s Hole pupfish. But these fish dwell close to the surface, where they feed off of microorganisms and other things. If you go deeper, you’ll soon find out why this cave is so dangerous. Not only is there absolutely no light at a certain point, but the shape of the cave and openings to completely unexplored chambers lay waiting to trap daredevils.

The last time someone died here, they attempted to measure the chasm using a weighted depth line. The two bodies that were lost inside were never found, and the depth line never reached the bottom. To this day, no one knows just how deep it goes, and what kinds of passageways it leads to. For good reason, visitors are not allowed here, and the pupfish will continue to exist in isolation.

You can learn more about the Devil’s Hole pupfish and the tragedies that took place there in this article.

The opening to the Devil's Hole cave in Nevada is shown, a narrow slit surrounded by sharp rocks.


Which of these underwater caves do you think deserves the title of the most dangerous? There are so many more caves out there as well, and we plan to add more to this list over time.

If you know one in particular that deserves to be on this list, be sure to let us know, and we will consider all recommendations.

When you’re done reading about underwater caves, check out our article on the world’s most dangerous caves. While most of these caves do not feature water, they are still infamous for their difficulty both in reaching them, and then exploring them in a safe way.

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