Sac Actun System is now officially the longest flooded cave system in the world
– With a total length of 347 kilometers, (216 miles) Sac Actun is the largest flooded cave in the world – It is the result of many hours of exploration and hard work leading to the connection of Sac Actun System 263 kilometers (161 mi) and Dos Ojos 84 kilometres (52 miles).
Cave exploration background
On January 10th, 2018, the Underwater Exploration “Group Gran Aquifero Maya” (GAM), succeeded in connecting two of the largest flooded cave systems making it the longest flooded cave in the world.
While Robbie has been actively looking for this connection during the last 14 years and adding new tunnels and galleries to this underwater maze, this stage of the project started in March 2017.
Until then, the 4 largest cave systems ranked as follow:
Ox Bel Ha System – 270 kilometers/ 163 miles
Sac Actun System – 263 km/161 miles
KooX Baal System – 93 km/57 Miles
Dos Ojos System – 84 km/52 Miles
The Sac Actun – Dos Ojos Connection
Sac Actun and Dos Ojos are now connected as a result of this intensive exploration.
According to the rules of caving, when two cave systems are connected, the largest cave system gives its name to the new one. Therefore the name of the Dos Ojos system disappears :'( .
Hence, the Sac Actun System is now the largest system in the world, with a length of 347 kilometers – 215 miles of flooded cave.
This finding is also very valuable, because this system supports a great biodiversity that live thanks to this huge reserve of fresh water.
But of course, underwater cave exploration is far from finished! New objectives pop up and the goal is now to connect Sac Actun with other nearby underwater cave systems in the municipality of Tulum.
Local explorers seek to better understand the underground of the Yucatan peninsula. And, they also investigate its biodiversity and the relationship of the humans with these ancestral waters. Of course, very concerned by their environment and pasionate, the aim is to manage an adequate use of the natural resources from this aquifer.
There will be more very ambitious stages to this project. Among those, stands the analysis of the water quality of Sac Actun System. As well, there will be studies of the biodiversity and its conservation; in addition to following up the mapping and investigating the submerged archaeological sites.
According to the Quintana Roo Speleological Survey (QRSS), the north of Quintana Roo alone hosts 358 submerged cave systems. It represents around 1400 km – 870 miles of flooded caves.
The word of the restless explorer, Robert Schmittner
“This is an effort of more than 20 years, to travel hundreds of kilometers of caves submerged in Quintana Roo mainly, of which I had dedicated 14 years to explore this monstrous Sac Actun System; now everyone’s job is to conserve it”
The word of the National Institute of Anthropology and History (INAH) and Director of the GAM Project, Guillermo de Anda
“This immense cave represents the most important submerged archaeological site in the world, as it has more than a hundred archaeological contexts. Along this system, we had documented evidence of the first settlers of America, as well as extinct fauna and, of course, the Mayan culture.”
Tulum: the mecca of cave diving.
Underwater explorers from all over the world have devoted their lives to their passion for exploration. Among them Bil Phillips, pioneer of the exploration of the Mayan aquifer. He founded together with James Coke, the Quintana Roo Speleological Survey (QRSS). The QRSS database gathers detailed maps of these complex systems. Today it is a valuable tool to understand and protect the aquifer.
Dedication to Bil Philips
Bil Phillips explored this wonderful underwater world until the last days of his life. For more than 40 years he devoted himself to understand the aquifer through the investigation of these ancestral waters.
Bil Phillips was an underwater cartographer and explorer, he passed away in November 2017.
You can think of cave diving as very demanding and more dangerous than reef diving, but when executed properly, cave dives are safe and extremely rewarding. After completing your cave diver training, you will travel to amazing places such as Bahamas islands and the Cenotes of Yucatan in Mexico, discover places only few people have ever seen and get a sense of exploration.
To become a cave diver you will have to go through rigourous training. The steps and levels can slightly differ from one training agency to the other, but your training will strongly depend on the instructors experience in cave diving and teaching. So make sure you get the right instructor for yourself.
Here are a few thoughts…
Can I become a cave diver?
First of all you need the right motivation: an interest for cave and for cave diving. If you’re a thrill seeker: pass your way!
Any Open water diver with sufficient experience and habilities can start a cave diving training program. You should be confident diving in low-light and low visibility conditions. You should be qualified or comfortable learning in a two-tanks system, either in sidemount or backmount configuration.
Cave diving demands a serious and confident approach, and discipline to meticulously conduct every dive, every time.
Three torches (Primary light source and two backups)
Reels and spools
Make sure to talk to your instructor before purchasing any item, to ensure that you’re getting the right gear.
Where can I learn to cavern dive?
First step of the full cave diver training, you should do your training in a cave diving area, to get real experience, and inspire you to continue your training to cave diver. The Cenotes of Mexico in the Yucatan Peninsula offer amazing training and diving sites, and remain one of the most popular cave diving destination in the world.
Where can I learn to cave dive?
The cave diver training is a two step course. During the first part, the introductory course you will learn to complete simple cave dives following a single continuous guideline.
The final part of cave training is mainly about adding complexity to navigation inside the cave. For that last part of the training we highly recommend the caves of Mexico. These very complex systems offer a large quantity of dive sites and scenarios possibility for training. The warm water and shallow caves will enable you to stay longer underwater, practice and focus on cave related skills.
The Cenotes of Yucatanoffers to divers the possibility to experience a unique type of dive: cavern diving in the Cenotes.
Diving in Cenote will give you a hint of what cave diving looks like in case you are yet undecided to become a cave diver or just want to enjoy the experience once.
What is a cenote?
The word “Cenote” comes from the Mayan “dzonot”. Cenotes are sinkholes created by the collapse of the limestone rocks, filled with crystal clear water.
The Yucatan penninsula is covered with Cenotes. They are found almost everywhere, some remain undiscovered deep in the jungle and others are right in the center of cities and villages. Furthermore they can have all sizes and shapes, some have underwater passages, some offer large pools while others are vertical pits. The Maya considered the Cenotes were sacred doors.
Diving in the Cenotes of Yucatan
Diving in the Cenotesis an exciting experience. You will enjoy the best diving conditions you can imagine. The water is crystal clear and the visibility is incredible, there is very little current and the water is warm all year around (25°C/76F). The underwater caves feature lots of speleothems (stalactites, stalagmites, columns, flowstones…) and stunning sunrays penetrating the darkness of the cave through small openings in the ceiling.
What certification is needed to dive in a Cenotes?
To discover the cavern part of the Cenotes on most sites you will only need an Open Water certification or equivalent, good buoyancy skills and a great level of comfort.
And if you want to go further you will need to get cave diving training and your guide can give you all the necessaries informations.
Formations of the Cenotes
These unique formations are due to a sequence of geological and climatic events. Several million years ago, the Yucatan penninsula was submerged by the ocean and arrised during the glaciation period, when the sea level drops.
Cenotes are formed by dissolution of rock creating a void bellow the bedrock and the subsequent collapse. These collapses occur during periods when the water table is below the ceiling of the void, since the rock ceiling is no longer buoyantly supported by the water.
What are speleothems?
Speleothems are cave formations resulting from mineral deposits. They take various forms, depending on whether the water drips, seeps, condenses, flows, or ponds. The most known speleothems are: • Stalactites: hanging from the cave ceiling • Stalagmites: the “ground-up” counterparts of stalactites • Column: when stalactites and stalagmites meet or when stalactites reach the floor of the cave • Drapery, curtain or bacon are thin sheets of calcite hanging downward • Flowstone: covering floor and walls of a cave • Soda straws: very thin but long stalactites having an elongated cylindrical shape
You will observe all of these mineral formations and many more in cenotes.
What is the halocline?
A halocline is a type of chemocline caused by a strong, vertical salinity gradient within a body of water. Because salinity (along with temperature) affects the density of water, it plays a role in its vertical stratification. In Cenotes, you will discover this very characteristic and fascinating phenomenon of Haloclines. And you will observe it particularly cleary in Tajma Ha Cenote and Eden Cenote.
The phenomenon is very visual and the demarcation between fresh water and salt water is very clear. In the presence of a halocline, when ascending from the salt water layer (below) to the fresh water the diver can have the feeling of floating in air over water.
In which Cenotes can we do cavern diving?
Here is a list of the most reknown cenotes in the Riviera Maya. There are many more to be discovered and for the most adventurous divers wanting to experience new dive sites consider a trip to the Cenotes Yucatan around Mérida and add the culture and the culinary experience to your diving.
Depth: 40 meters/ 120 feet Difficulty: Difficult
The Pit is one of the deepest Cenotes of Yucatan (130 meters) and is part of one of the biggest cave system in the world. You will enjoy the amazing light beams going all the way down to the sulfide layer at 30m.
Taj Ma Ha
Depth: 15 meters/ 50feet Difficulty: Moderate
The Cenote Tajma ha is located 5 km south of Puerto aventuras. A fairly demanding dive due to the multiple depth changes, you will be rewarded by the stunning beauty. You will observe lots of stalactites, stalagmites and fossils, 3 other Cenotes on the way with amazing light effects and come accross the halocline a few times.
Depth: 40 meters/ 120 feet Difficulty: Difficult
The Cenote Angelita is one of the deepest cenote in the Riviera Maya. It is particularly known for its sulfuide layer looking like an underground river flowing around a small island whith a few trees. Under the cloud, you will experience total darkness. This is an exceptional dive full of sensations and is for experienced divers only.
Cenote Car Wash
Depth: 16 meters/ 50 feet Difficulty: Easy
Aktun Ha better known as Car Wash is located near Tulum. Its name come from the fact that people used to come to this cenote to wash their cars. In summer the open water pool is covered by a thick and dense layer of algae bloom whith very reduced visibility. Below this layer the water is crystal clear with subtle green brightness. You will meet turtles, fish and possibly a small crocodile. And you will enjoy the amazing beauty of the water lilis.
Cenote Chac Mool and Kukulcan
Depth: 14 meters / 50 feet Difficulty: Easy
The Chac Mool Cavern Line leads you through a large well lit Cavern Zone with very impressive breakdown formations and spectacular views of the jungle from underwater. You will see tree roots growing down into the water along the edge of Main Entrance and dive a hypnotic halocline passage. Halfway through the dive you can surface in a beautifully decorated air dome before continuing on through a cathedral of speleothems.
Cenote Kukulkan offers in winter one of the most amazing light show you can imagine.
Depth: 15 meters/ 50 feet Difficulty: Easy
The Cenote Eden also known as Ponderosa features beautiful light effects and a wonderful halocline. In the open water pool you will observe many colorful fishes.
Depth: 15 meters / 50 feet Difficulty: Easy
Chikin Ha means “Western Water” it is a very large half moon cenote with crystal clear water.
The permanent guideline begins in the open water of Chikin Ha and traverses over to Cenote Arcoiris (Cenote Rainbow) through a large halocline tunnel. On the way back to Chikin Ha you will see fossils, crystal formations and speleothems.
Depth: 9 meters / 30 feet Difficulty: easy
Dos Ojos is probably one of the most known Cenote dive thanks to the I-max movie “Amazing Caves”. The cenote offers two different dives, the Barbie Line, a circuit with massive columns and stalactites. The Batcave Line is more like a dark cave as you swim around an air bell with very little light entry. All along you will enjoy the variety of its delicate formations.
Depth: 7 meters / 30 feet Difficulty: Moderate
As the name suggests, you will see along your dive, at the bottom, some animal skeletons. And above all this is not even the hit of these dives! This cave is amazingly decorated with white speleothems. the nearby surface will offer stunning reflexions of these formations. Just hold your breath and enjoy! And if you need more look between the roots for blind fish 🙂
Depth: 7 meters / 30 feet Difficulty: Average
Dreamgate requires really good buoyancy skills as it is very shallow and has very low ceiling. Very decorated with delicate formations, make sure you dive close to the line to limit the impact of your bubbles or an unfortunate fin kick. We love the place and want to enjoy it for a long time.
Depth: 40 meters / 120 feet Difficulty: Very difficult
Zapote is one of the most demanding Cenote dive as it is deep and fairly dark and you will also encounter a sulfide cloud. But most of all it is very rewarding as, out of this cloud, you will face very special formations, in the shape of a bell. Keep in mind that not only they are very surprising but the are still new to science.
Depth: 8 meters / 30 feet Difficulty: Easy
Casa Cenote is one of the easiest cenote dive. You will dive directly under the mangroves and get the chance to meet some marine life since the Cenote is directly connected to the ocean. Most of all you will swim across a dense halocline and observe some beautiful lights effects.
Remipedes are blind crustaceans living in coastal aquifers which contain saline groundwater, with populations in almost every ocean basin explored, including in Australia, the Caribbean Sea, and the Atlantic Ocean.
Remipedes are venomous crustaceans, and the only ones of their kind, first discovered in the 1980s. Their name comes from Latin for “oar-footed” because of the beautiful movement of their many pairs of swimming legs.
Contact us for some guided cave dives get the chance to observe live remipedes.
And if you want to become a cave diver we will be happy to orientate you through your training.
In Cave Diving a Restriction is a narrow passage where two divers could not fit side by side or one on top of each other. Learn how to get through during the Full cave training. A few shots of some minor restrictions put together by my friend and dive buddy while Cave diving in the Cenotes of Mexico
Cave diving in these amazing mexican caves requires proper training. Don’t hesitate to contact us for more information on cave diving training.
All the Cenotes offering the possibility to do a Cavern dive present a board with very clear and explicit pictograms regarding the safety rules for cavern diving. We encourage you to have a look at it and ask your guide what may remain unclear.
– No Knives – No Gloves
– No snorkel – Gear streamlined and stowed
– Do not remove any stalactite, rock, fossil from the dive site
– No touching, no scratching, do not leave any visible mark
– Divers go behind the guide in a single file, maximum 4 divers per guide
– The guide must be a Divemaster or Dive Instructor in teaching status and be a certified Full Cave Diver
– Manage your Air using the rule of thirds
– Natural sunlight should be visible at all time, do not go beyond natural sunlight
– Follow the guideline at all time, do not go off the guideline
– Adopt good trim, buoyancy and propulsion techniques,
– Do not remove sediment, it might result in the loss of visibility and it is part of the cave formation, so you should treat it respectfully
– Do not pass through restricted area, at all time 2 divers should fit side by side or one on top of each other
– Limit your penetration to 60m/200feet even when sunlight is still visible, you should not pass this distance without proper Cave diving training.
Remember: There is nothing beyond these limits worth dying for! Do not put your life at risk and follow the rules.
The cavern dives are full of surprises and amazing dives all year around, enjoy!
We are passionate and experienced instructors and guide and will love to show you this amazing and unique art of nature in the safest way possible.
A cave dive playing in the halocline, meeting with remipedes
This cave is just amazing, dark with a very well defined halocline. Recommended to dive with Nitrox and with stage side mount or stage back mount configuration as it is fairly deep and you will want to stay as long as posible.
Halocline: from Greek hals, halo- ‘salt’ and klinein ‘to slope’
The halocline is the area within a body of water that marks a drastic change in salinity.
Haloclines are common in underwater caves near the ocean. The fresh water, less dense, forms a layer above the salt water from the ocean. For cave divers, it causes the optical illusion of air space in caverns. Passing through stirs up the layers and blurs the vision.
The halocline itself is responsible for the formation of the cave systems. The mixing of the saltwater and freshwater results in reactive brackish water that dissolves the limestone, eroding the rock and enlarging a cave’s passageways.
Because different water densities meet at the halocline and both organic and inorganic particulates accumulate there, it is chemically speaking an intriguing place.
Contact us for private guided dive in hidden side passages.
You are planning a dive trip to the Yucatan Penninsula in Mexico? Then you might have come accross some amazing pictures of the beautiful Cenotes. Once stunned by these pictures you probably want to see it with your own eyes and live the experience.
But this question keeps popping up: is Cenote diving for me?
What are Cenotes?
Cenotes are sinkholes distributed all over the Yucatan Peninsula. They are the window to the underwater caves and caverns. And they are one of the main dive attraction in the area and one of the top dive destination in the world.
Those caves are highly decorated with stunning formations such as stalagmites and stalactites which makes them very unique.
Your first Cenote diving experience will probably be a cavern tour. You are not required to have a cave diving certification as you will not be technically entering the cave.
What is a cavern dive?
A cavern dive is the exploration of a natural overhead environment while remaining within sight of natural light.
When diving in the Cenotes you will always see natural light and have a sight of a direct way out of the cavern. However do not underestimate safety by thinking it is an easy dive. And here are some thoughts to consider before going for a cavern dive.
Will I be swimming in tight places?
No you won’t!
It is a requirement for all cavern dive in the Cenotes to go through areas where two divers can fit side by side at all time. You will not swim in any tight areas.
Should any problem arrize you will be able to swim side by side with your guide to exit the cavern.
Can accidents happen while Cenote diving?
Yes, it can happen…
Your cavern guide should be a qualified divemaster or instructor in teaching status and a certified cave diver. Of course the more experienced the better the guide can react to a bad situation. And the more he/she knows the site, the better he/she can handle the situation.
Cavern diving by the book, is really safe. The conditions are optimal: shallow dives, no current, great visibility, group size limited to 4 divers maximum per guide and all divers should be experienced.
We recommend you to choose carefully your dive operator or guide. And remember the most experienced the guide the better he/she can show you around and yet commit to safety and conservation.
Is it dark down there?
Yes it is!
Some parts in the Cenotes are very dark and darkness can alter your sense of orientation, and you a feeling you could get lost easily. This is why everyone is diving with a dive light.
Your guide should be carrying all his/her full cave gear that includes a bright and long lasting primary light used for showing you around and for communication as well as 2 back up lights. And yourself should carry at least one dive light.
The waters in the Cenotes are crystal clear, and will stay that way if all divers follow the basic rules: maintain good buoyancy, swim using non silting kicking techniques and follow the guideline.
Will I be able to find my way?
Yes, as long as you follow the Guide Lines
One of the main safety rule in cavern diving in the Cenotes is referencing the guideline at all time. Your guide will explain how to identify it, how to use it and where to position yourself at all time. The same guideline will show you the way out. You should also be able to rely on your guide to follow them at all time.
We strongly recommend to dive the Cenotes. It is a unique and magical experience. Always make sure you dive well within your limits and remember the golden rule: anyone can call the dive, at any time, for any reason. So, do not hesitate to do so whenever you don’t feel comfortable.
When comes the time for you to book your dive tour to the Cenotes, remember that safety is important. Cenote diving is for advanced divers and you should be sharp on your dive skills, so don’t hesitate to refresh them by a couple ocean dives before you head for the cenotes.
Enjoy your Cenote dive 🙂
Contact us for some private guiding or personalized group packages: CONTACT