Mexico is known for having the greatest concentration of cenotes in the world. In the Yucatan Peninsula alone you can find over 6,000 cenotes. The ancient Mayans believed that these sinkholes were sacred wells and used them as grounds for different rituals, including human sacrifices. Leaving aside their grim history, the cenotes are now a magnet for divers and adventure-seekers.
Scuba diving in a cenote is one of the main activities divers take part in when they’re visiting Mexico. It also helps that even those holding an Open Water certification can dive in many of the cenotes, as cavern divers don’t go very deep into these sinkholes. Nonetheless, there are plenty of opportunities for cave and technical divers that wish to venture into the darkness.
Diving the cenotes of Yucatan is possible throughout the year. However, May through September is considered the best time to dive the cenotes because you can enjoy more light into the sinkholes.
The cenote water temperature remains around 25° C/77° F year-round.
The water inside the cenotes does not have strong currents and they generally lack any current at all.
The visibility in a cenote is excellent, often reaching 100 meters (328 feet). It can, however, worsen due to inexperience divers that do not know how to control their buoyancy and may stir up the sediments on the bottom.
The marine life in the cenotes is rather unimpressive. Because of the conditions found here, only a number of species manage to survive in these waters. Some cenotes are void of life while others may offer encounters with catfish, mollies, and tetras. These animals live in the freshwater found in the upper section of the cenote. In the caves, you may spot blind fish; they are completely white and have no eyes, as they have adapted to the darkness and are more energy-efficient this way.
The cenotes are filled with stalactites, stalagmites, and columns. The stalactites are the result of water dripping from the ceiling, resulting in buildups of calcium carbonate. Stalagmites occur when the droplets of water fall to the bottom, so the calcium carbonate builds up from the bottom upwards. Columns are just stalactites and stalagmites meeting and forming a pillar. Large rock formations take thousands of years to form, which is why it is important for divers to keep a safe distance to avoid destroying them.
Showered in light in a cenote. Photo by Gustavo Gerdel
There’s an eerie atmosphere in cenotes, and the reason for this is the light that manages to penetrate the darkness. But there’s another factor that adds to this otherworldly experience, and that’s the hydrogen sulfide cloud. This is caused by the vegetation surrounding the cenotes; as it falls down and decomposes at the bottom of the cenote, it produces hydrogen sulfide which looks like smoke in the water. It’s like you’re swimming above an underwater swamp.
The tunnels of the cenotes were once dry, allowing prehistoric animals to go inside them. It’s not unusual to see the bones of animals still inside them, some dating back approximately 15,000 years. Some cenotes even hold human bones.
Since the cenotes were sacred places for the ancient Mayans, some of them contain ceramic bowls which have most likely been placed there as part of their rituals.