How are the cenotes of Tulum formed?

The area around Tulum is very flat. There are no hills, mountains, or even rivers.  Many thousands of years ago the land where the cenotes are situated was under the sea and parts were a coral reef. Over many years the seabed rose up and the water levels dropped, leaving the coral exposed to the air, eventually turning it into limestone which you can still see today. Around 66 million years ago the Chicxulub asteroid hit a few 100km from Tulum causing cracks and sinkholes. Over many thousands of years the rain seeped through the very porous limestone into the cracks and formed caves, pushing its way into the sea. Underground rivers had been formed. Many thousands of years later the Ice Age came and the water levels in the underground rivers dropped as the water went to the North and South Pole as ice. In places the ceiling collapsed as there was no water to support it thereby making more sinkholes. During this time when the caves were dry, rainwater again passed through the limestone but now drip by drip it formed the stalactites and stalagmites. When the Ice Age finished the water levels rose again as the ice melted and the caves were flooded as they are today. The ceiling collapses are the entrances and exits. The stalactites and stalagmites are still there as are animal and human remains, trapped or left there when the caves were dry.

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​We usually start our day by picking you up from your hotel in Tulum at 10am. Our preference is to start a little later than most Tulum dive shops so as to help avoid the crowds. As we are not your typical dive centre we take out the hassle of you having to come to us, we come to you. In our communication we will have already organised sizes of dive equipment to bring, plus spares. The homemade Mexican food will already be packed and so  its straight off

​to the cenote dive sites. Most of our cenotes around Tulum are within about 15minutes. Once at the cenote we have an orientation of the site incorporated into the start of the dive briefing, where the cavern diving rules are explained and we take a look at the map of the cenote. Then we prepare the equipment, we encourage our divers to be able to prepare and adjust the scuba diving equipment they´ll be using, but of course we are happy to help with anything forgotten etc. Once content with the equipment we go through the use of the lights for communication and how to signal pre determined air pressures and other signals used in cenote diving. Next our highly experienced dive guide will give you the amount of weight we think you´ll need which can be a bit different to what you may have used before due to factors such as diving in fresh water or using a thicker suit as the water is a bit cooler than tropical ocean water. Once in the water we will confirm these weight with a quick buoyancy check with spare weights available should you need to add or take away a few kilos. Regulators checked, bubble check, lights on and now we descend. All our dives are a minimum of 45 minutes, obviously depending on gas reserves but most cenote dives here are shallow and that time is easily reached. In between dives we will eat lunch and in some cases take a short drive to the next cenote dive site. We group which cenotes we go to as to minimize this drive time. Usually when we start our second dive most other dive shops have already left due to us starting later so we often have the cenote dive to ourselves. Same procedure for the second dive, orientation and briefing about any particular wildlife or features expected to be seen. Then into the water for our second dive. We normally return to Tulum between about 3 and 4pm and drop you back off at your hotel.​​​​