Blue holes are incredible geological structures that provide some of the most amazing places to dive that the ocean has to offer.

Forming a part of the lighthouse reef atoll, and boasting a deep blue color with a biodiverse reef surrounding its rim, visiting the Great Blue Hole of Belize is a truly mesmerizing experience.

Whether you are familiar with the Big Blue Hole or not, these are some things you should know about it before visiting.

1. What Is the Big Blue Hole In Belize?

The Big Blue Hole is a world-renowned natural wonder located in the Caribbean Sea. It is a large underwater sinkhole that holds the title of the largest Blue Hole on Earth, and thanks to its biodiversity and perfect shape, it has become a hotspot for tourists and nature lovers.

2. How To Find the Belize Hole

The Blue Hole can be found off the coast of Belize, in Central America. Forming part of the Belize Barrier Reef System, the sinkhole lies near the center of the Lighthouse Reef, with approximate coordinates of 17.3184° N and 87.5349° W.

The Belize hole can be found near the center of the lighthouse atoll reef
The Belize hole can be found near the center of the lighthouse atoll reef

3. Appearance, Size, and Shape of the Big Belize Hole

The Big Blue has a near-perfect circular shape with a diameter of approximately 1000 feet (300m). The walls of the sinkhole are covered with giant stalactites, stalagmites, and limestone structures that give its deep blue color a powerful yet mesmerizing touch all the way down to its depths of 400 feet (125 meters).

4. How the Great Blue Hole Was Formed

When sea levels were lower, acidic water was believed to cut through the soluble limestone over thousands of years, forming an intricate underground limestone cave system.

During the last glacial period (ice age), seawater levels rose and put pressure on the ceiling of the cave, eventually causing it to collapse from the weight.

As the geological process is slow and changes over thousands of years, it’s difficult to predict the time of the cave roof falling in, but it’s assumed that it occurred approximately 15,000 years ago.

5. Why is the Belize hole so blue?

The big blue hole is similar to other oceanic sinkholes, which are also referred to as blue holes. 

The deep blue color that can be seen around the big blue is primarily from its depth and the way light interacts with the surrounding water.

Due to the depth of the big blue hole, very little blue light can penetrate its depths, thus giving it a darker blue color in the center, while the shallower rim of the hole remains bright blue.

6. What’s at the Bottom of the Blue Hole?

The bottom of the Belize hole is dark and, for the most part, barren and lacking marine life due to the lack of penetrating sunlight.

The consistency of the hole’s floor varies but is mostly composed of fine sediment, sand, and remains from the collapsed cave.

As there is very little light, photosynthesizing aquatic life such as kelp and coral are not able to survive, which keeps the diversity low; however, there are some unique species that can be found when exploring the hole.

7. Coral Diversity in the Belize Hole

As mentioned above, the lack of light reaching the bottom of the hole prevents coral from forming at its depths; however, the surrounding area of the hole is abundant with coral life and diversity.

The Belize Barrier Reef System is the second largest barrier reef in the world
The Belize Barrier Reef System is the second largest barrier reef in the world

Forming part of the Belize Barrier Reef, which is the second-largest barrier reef system in the world, second only by Australia’s Great Barrier Reef, a diverse array of hard and soft coral can be found surrounding the sinkhole.

Staghorn coral, brain coral, fire coral, finger coral, and lettuce coral are but a few examples of coral species that are abundantly found around the Belize Blue Hole.

8. Animal Diversity of the Big Blue

With the lack of photosynthesizing organisms in the hole’s depths, the diversity of life is greatly limited. That said, there are a variety of animals that can be found in the hole and a wide array of species that make their homes in and around the surrounding reef.

Some species that can be found in the hole include pelagic fish such as tuna, jacks, groupers, and occasionally sharks. It’s also possible to spot bottom dwellers such as crabs and lobsters; however, these are more common on the hole’s walls or closer to the ocean’s surface.

That said, the shallower waters of the hole and the surrounding reef are home to a vast diversity of animal life, which includes an array of tropical fish, reef sharks, turtles, rays, invertebrates, crustaceans, mollusks, and occasionally dolphins.

9. Threats to the Ecology of the Big Blue

The Big Blue Hole and its surrounding reef face numerous threats to its ecology, including climate change, unsustainable fishing practices, pollution due to bad waste management systems, and coastal development, which leads to sedimentation and potentially the destruction of coastal habitats such as coral reefs.

Tourism has also had a large impact on the ecology of the area. Due to the sinkhole’s popularity, thousands of tourists visit the hole each year, many of which do not follow safe diving practices or conscious tourism.

This has led to physical damage to the fragile ecosystem.

10. Conservation of the Belize Hole

The Belize Hole is considered a marine protected area (MPA). This management of the area aims at regulating human activity, such as recreational practices and fishing regulations. This helps conserve the natural environment and the species that come with it.

Educating visitors on safe and sustainable tourism practices is essential to the atolls ecology
Educating visitors on safe and sustainable tourism practices is essential to the atolls ecology

Furthermore, large efforts have been put in place by coastal communities to reduce waste and educate tourists on responsible tourism.

Constant tracking and monitoring of the hole and its surrounding reef is conducted by scientists to ensure the area is healthy,  which often provides helpful insight into how the ecology of the area works and what we can do to conserve it.

Although the hole itself is not listed as a UNESCO World Heritage Site, it is part of the Belize Barrier Reef Reserve System, which has been since 1996.

11. Requirements for Diving in the Belize Hole

The Belize Atoll and Blue Hoole offer a wide variety of SCUBA dive sites, but unfortunately, unless you are a specialized diver, you won’t be able to visit the bottom of the Belize Hole on SCUBA.

This is simply because it’s too deep, and recreational SCUBA divers with advanced certifications may only dive down to 30 meters if you have trained with PADI and 40m if your training was done with SSI. You will also need to have completed at least 20 dives before doing your advanced course.

It’s also possible to dive the blue hole if you only have your open water, although your depth will be limited to 20 meters. You should also note that you will need to have last dived within six months of visiting the big blue, or a refresher course will need to be conducted.

12. Freediving the Blue Hole in Belize

Just because you can’t reach the bottom of the hole on SCUBA, it doesn’t mean you can’t go there, although to do so requires years of training and a strong mental capacity.

Freediving is popular in the Blue Hole, thanks to its crystal clear waters, lack of current, and magnificent structure.

To do so, you will need the required certificates, as well as to follow freediving safety precautions such as planning your dive, pre-dive prep, and ensuring you have a diving buddy.

Although the freediver in the video below was done in Dean’s Blue Hole, the stunning performance by Guillaume Néry, a famous French freediver, gives a good idea of what the experience may be like.

13. Activities for Non-Divers

The Big Blue Hole is primarily known for its mesmerizing diving and its SCUBA that brings in most of the tourism; there are still a variety of activities for visitors that don’t dive.

Snorkeling on the surrounding reefs and boat trips are popular and allow non-divers to explore the biodiversity of the reef while spotting wildlife, both on top and below the water’s surface.

Nearby islands can also be explored, where tourists can relax, swim, and enjoy local meals while taking in the communities culture.

14. Discovery of the Blue Hole

The Big Blue Hole was made popular by the renowned explorer Jacques-Yves Cousteau in 1971 when he and his research team explored the Belize coast.

After this exploration, a documentary television series called “The Undersea World of Jacques Cousteau” was created, which brought popularity to the hole and its surrounding reef.

15. Safety Precautions When Visiting the Belize Hole

As the destination is popular, there are a wide array of tour operators you can choose from, many of which uphold high standards of safety, although it’s important to ensure you have chosen a reputable company with high standards.

When visiting the hole, you should ensure to follow the guidelines provided by your tour company.

Furthermore, it’s good to keep the following in mind before and during your trip:

  1. Ensure you are in good health
  2. Closely monitor weather conditions
  3. Stay hydrated and fueled up
  4. Stay with your group
  5. Follow safe diving practices
  6. Respect the environment
  7. Have an emergency or backup plan


When is the best time of year to visit the Belize Hole?

December to January are the busiest times at the Big Blue, although, during March and April, the visibility is still high, and the water temperature is perfect.

Are sharks common in the Belize Hole?

As there isn’t much life in the hole itself, spottings of sharks are rare. That said, living in the surrounding reef, hammerhead sharks, nurse sharks, and reef sharks are commonly seen.

Are there any secret blue holes I can visit, like the Belize Blue Hole?

Although they aren’t secret, there are some less common blue holes you can visit. A few include Dean’s Blue Hole (Bahamas), Dragon Hole (South China Sea), and Blue Hole of Dahab (Egypt).

Does the Big Blue Hole have underwater caves?

The Big Blue has various underwater caves and passages that can be explored if you have the correct diving qualifications

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