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The Wonder of Mexico's Cenotes with Tom St George

Gran Cenote Mexico Tom St George

The entry point at Gran Cenote is shared by divers and snorkellers

For photographer Tom St George diving in Mexico’s cenotes is a passion. Here he shares his guidelines for how to make the adventure safe, exhilarating and sustainable

An open-water diving qualification is all you need to experience the wonder of cavern diving in the cenotes of the Riviera Maya in Mexico. 

There are more than a dozen cenotes (pronounced se-NO-tays) commonly dived. While each is unique, they all share moderate temperatures, offer year-round diving and the promise of adventure. 

Cenote Angelita Mexico Tom St George

Cenote Angelita (‘little angel’) is a popular site in Tulum. At around 30m is a cloud of hydrogen sulphide, created by the decomposition of organic matter in the absence of oxygen. The cloud combined with a mound of debris from the collapse of the roof gives the surreal impression of an underwater lake with its own little island

Most of the cenotes are found along the now busy highway between Playa del Carmen and Tulum. They include the underwater garden of Cenote Carwash, the statuesque decorations of Dos Ojos and the amazing light show of Tajma Ha. With an advanced certification, you can also enjoy the deeper dive sites of the majestic Cenote El Pit and the haunting Cenote Angelita. 

The Yucatán Peninsula was once a shallow reef and is now a porous limestone shelf covered with forest and wildlife. There are no rivers here. Instead, the rainwater flows underground through a network of submerged cave systems, eventually reaching the sea. Mexico has nine out of the ten largest cave systems in the world.

Cenote Dos Ojos Mexico Tom St George

Dos Ojos (two eyes) is part of the longest known cave systems in Mexico and the world

The cenotesare the entrances to these systems and provide the only access to freshwater in the area. They were hugely significant to the Maya civilisation and are still important to the population of Maya people living in the state of Quintana Roo today. 

The name cenote is a Spanish corruption of the Maya word d’zonot, which means a place with access to water. The Maya consider the cenotes sacred and believe them to be entrances to the Mayan underworld, Xibalba, where gods live and spirits reside after death.

A cenote is a natural sinkhole created when the ceiling of an underground cave has collapsed. Some cenotes are vertical, water-filled shafts, others are shallow entrances created by just a partial collapse. These cave systems were formed when the sea level was much lower than it is today. Rainwater is slightly acidic, and so it slowly eroded the limestone as it percolated through the bedrock and carved out the caves. As water dripped from the ceilings of these caves it deposited some of the dissolved limestone to form the stalagmites and stalactites we can see today. As the water levels once again rose the caves became flooded. 

Cenote El Pit Mexico Tom St George

Viewing the branches of a tree in El Pit. The top 10m of this 40m-deep cenote is  fresh water, below 12m it is salty

In diving terms, a cavern is defined as the entrance area of an underwater cave where the daylight is still visible and is no more than 60m from open water. As cavern diving is conducted in an overhead environment, it is considered a specialised form of diving. While cavern diving certifications are available (these being the first step on the road to a full cave diving certification) they are not required if your diving is supervised by a qualified local cavern guide. Cavern guides are required to have at the minimum certifications of both divemaster and full cave diver. 

While a recreational cavern tour is very different from a cave dive, it borrows heavily from protocols used for cave diving. The most important being that there should always be a continuous guideline that you can follow to reach open water safely. In the event of a light failure, team separation or loss of visibility, this line is your lifeline. 

Casa Cenote Tom St George Mexico

Casa Cenote sits in the middle of an area of mangrove and is part of the Nohoch Na Chich cave system

Cenote Calavera Halocline Mexico Tom St George

In Cenote Calavera (Skull Cenote, which is also known as Temple of Doom) there are several halocines. Cave divers require specific training and must use lines to guide them


  • No touching (so no gloves)
  • Stay on the guideline at all times
  • No more than four divers per guide 
  • Each diver must have a dive light which should remain on for the entire dive
  • Stay within the cavern zonewith daylight visible at all times
  • Follow the rule of thirds: use a third of your gas in and a third of your gas out, leaving a third in reserve
  • Always dive in passages wide enough for two divers to pass side by side, which allows divers to gas-share in an emergency.

Cenote Carwash Lillies Mexico Tom St George

With a depth of 16m, the relatively shallow Carwash Cenote is known for its beautiful lilies 

Cenote Carwash Mexico Tom St George

Carwash Cenote

Cenote El Pit Shaft of Light Mexico Tom St George

The excellent visibility at Cenote El Pit makes it an amazing place for underwater photography, particularly when light beams stream through the entrance

Cenote Kukulkan Mexico Tom St George

Cenote Kukulkan

Cenote Ponderosa Mexico Tom St George

Cenote Ponderosa is home to a variety of fish, freshwater eels, turtles and aquatic plant life



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