Cave Diving

The Ultimate Guide to Cave Diving in Mexico

Mexico is one of the most popular cave diving destinations in the world. Perhaps the most popular. Why is that?
Well, for a start it has wonders of the natural world like the Sistema Sac Actun – the longest underwater cave system on the planet (this was confirmed in 2018 when explorers discovered that the huge Sistema Nohoch Nah Chich and Sistema Dos Ojos were connected). But there’s one not-so-secret weapon in Mexico’s cave diving arsenal:

Cenotes.

Cenotes are the truly stunning natural sinkholes of the Yucatan Peninsula. Filled with water. Filled with wonderful life – in technicolour. They’re the setting for possibly the most spectacular cave diving experiences anywhere on the globe, or just beneath it. If you’re already a seasoned cave diver and you haven’t gone diving in a cenote…

It’s time to start packing your bags and booking your trip. And if you haven’t tried it out already but you always wanted to learn how to cave dive, where could be better?

You’ve got the brilliant local diving community, packed with world-leading instructors. You’ve got the Mexican climate, flora and fauna. Most of all, you’ve got the incredible cenotes. They’re going to make your experience truly unforgettable. Whether it’s your first dive or your hundred and first.

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Cave Diving versus Cavern Diving – yes, there’s a difference

Let’s start with some basics. What is cave diving? Isn’t it just the same as cavern diving?

Not at all. “Cave” and “cavern” sound so similar that it’s easy to start thinking they mean the same thing. But picture a cavern for a moment:

Are you imagining a huge open space, perhaps with a few stalactites hanging down? Is there some natural light shining down through cracks in what might be a ceiling, sure, but a ceiling that’s far overhead and which allows easy access to the outside world?

Now start imagining a cave. It’s a darker, enclosed space. It might be a little more confined. The way you move is going to be very important indeed here. Because there’s no guarantee that there’s going to be room to really manoeuvre – or any natural light at all…

Most of the splendid cenotes of the Yucatan Peninsula in Mexico are caverns which open into underwater cave systems. This leads to at least five very important differences:

1. Natural light – in a cavern you will almost always be able to see a source of natural light. If in doubt, swim towards it. In a cave, the way out might not be so clearly signposted. In fact, there may be no light at all.

2. Cave diving equipment is special – you can go cavern diving with your normal scuba gear. The same kit you’d use in the open water in places like the Mesoamerican Barrier Reef (if you’re a diver and you’re in Mexico anyway, you can’t miss this). For cave diving, you’ll need specially designed gear.

3. The restrictions you’re under – a cavern dive is usually limited in depth to 70-120 feet (that’s 21-40 meters) beneath the surface. That’s how far the light can penetrate from overhead. You’ll also have limitations in permissible starting visibility and of no decompression. Cave diving puts you beyond all of those restrictions.

4. The world you’re in – this is one of the starkest and most thrilling differences between cave diving and cavern diving. The dark subterranean world you enter in a cave is full of new and intriguing life, cleverly adapted to its lightless environs. Caverns are beautiful. But caves can be truly alien in their splendour.

5. The training you need – while both caves and caverns are overhead environments which require some specialised training before you can safely dive there alone, cave diving requires that you learn a whole lot more…

Things to consider before taking a Cave Diving Course

If you’re trying to work out whether cave diving is for you, there are a couple of things you should consider:

First, your experience level. Cave diving is only recommended for very experienced divers. You need advanced level qualifications or be willing to train to get them. You’ll want to inventory things like your:

Buoyancy control – this should be absolutely spot-on.

Finning techniques – you should be well practised at skills like the helicopter, frog kick and backward finning.

Diving procedures – your knowledge of diving procedures in general needs to be recent and regularly updated.

Secondly, you need the equipment. Cave diving in overhead environments can be dangerous and you need to be prepared. You’ll want to be intimately familiar with your kit. As well as all of the other safety requirements which you need to take on board to do this thrilling activity safely.

What are the most important cave diving training requirements?

You will need evidence that you possess the skills above in the form of your:

Advanced Open Water certification or its equivalent

Cavern or Overhead certification

There’s also a standard minimum requirement that you complete 50 logged dives. But for real safety and to truly build your confidence and skills to where they need to be, 100 logged dives might be more what you should be aiming at.

You also need to be 18 years old, but that probably goes without saying.

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What will you learn during a cave diving course?

Make no mistake, a cave diving course is tough. It’s deliberately designed to be that way. Not to put too fine a point on it, there’s a lot you need to know in order to dive in a confined space underground safely!

Of course, you’ll start off practising the techniques and drills in shallow water and go through simulations in places where there is no danger. But you should still be ready to deal with situations which might feel stressful to you. You will practice things like:

1. Zero visibility training – how to recover a lost line and navigating when visibility is negligible.

2. Navigation training – how to tell which way you’re going in a cave.

3. Buddy and communication training – how to use hand and light signals, as well as to communicate through touch contact. Everything you need to know in order to work with your dive buddy, including in an emergency.

4. Buoyancy training – making sure you’re as close to perfect as possible when it comes to your trim and buoyancy.

5. Propulsion and kicking techniques – because you need to use certain types of kicks so as to not throw up a cloud of sediment.

That’s not to mention working with a reel, line markers and your pre-dive equipment checks. Actually, your equipment is an important point to consider…

What cave diving equipment will you need?

This is one of the major differences between cavern diving and cave diving. For cave diving, you need a certain amount of specialised gear. This will probably include:

  • A dry suit – this is not a requirement, but it is recommended due to the duration of the dives. If you get cold, you can’t just get out!
  • A buoyancy device, backplate and harness.
  • Double tanks, sidemount or rebreathers.
  • A powerful hand-attached light source and two spare dive lights.
  • Stiff fins are a popular choice as they make it easier to not kick up silt.
  • Possibly a dive computer
  • A spare dive mask
  • A sharp knife
  • Markers
  • A wet note notebook

Practicing Cave Diving Safety

A cave diving course can be tough. But your instructor is there to train you how to deal with very real and potentially deadly cave diving dangers. For instance:

Your visibility is at zero. Your buddy is out of air and entangled in the line. What do you do?

You turn around. When you turn back, your buddy is gone. Now what?

You can’t see anything. You can’t find the line. How do you get a hold of it?

If you’ve had proper training, if you’ve got your certification and you’re diving with a certified cave diving guide, you’ll know. Being fully prepared for situations which might never happen is the end goal of your cave diving training. You’ll feel safe because you know how to be safe.

But because of the seriousness of these situations, of course, the training has to be hard. When it comes to practising cave diving safely though, there are some basic rules you should always follow:

5 Golden Rules for Safe Cave Diving

1. All cave divers should be trained specifically for cave diving – the training course for ocean diving you did that one time is not sufficient.

2. Avoid going under 40 meters in any cave, if you are diving with normal air – the nitrogen in air acts as a narcotic at high pressures, diminishing any diver’s judgment and performance.

3. Run continuous guidelines at all times – a guideline should be run from open water so that divers can use it to find their way out of the cave.

4. Play by the rule of thirds – one-third of each diver’s air should be used to enter the cave, leaving one-third for exiting the cave and one third for emergencies.

5. Don’t forget how important light is – every diver should carry one main light and two backup lights.

Why get a professional cave diving guide?

If you’re a certified cave diver, strictly speaking, you don’t need a guide. So why get one?

For a start, local knowledge. You can’t beat it. A professional cave diving guide will be familiar with local cave systems and know how to make your dive both safer and far more interesting than meandering around a random cave in the dark. If you want to explore all of the underwater caves of the Riviera Maya, for example, it would take years. A decade or even more perhaps! Obviously, not every single cave is going to be worth your time. Especially if you’re only visiting for a limited period.

Get a local guide who can show you the best places to go for your interests and skill level. Plus, you won’t waste time and air searching for the main permanent line (they’ll know where it is), the offshoot line to a particular passage or room that you’ve heard of (they’ll be able to show you) or going in the wrong direction (they know which way is which).

Another reason to get a cave diving guide – one which should be important to all true cave divers – is to protect the fragile underwater ecosystem. If you’re not familiar with the local cave environment, you risk causing major damage to it – even with the best of intentions. With a professional guide, you have the knowledge and experience to dive safely.

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Ready to try cave diving? Here are the top 5 best cenotes for cave diving in the Riviera Maya

You’re on the Yucatan Peninsula. You probably don’t have time to try cave diving in all of the cenotes in the Rivera Maya. So which ones are really unmissable?

Chan Hol – “Little Hole” cenote is one of the smaller sinkholes on the Yucatan, but it offers some very interesting dives. Investigate the Mayan pottery near the entrance, the amazing light pool and then venture on into the depths.

Nohoch nah Chich – take long shallow dives in the cave which was, up until recently, the world’s longest underwater system. The stunningly clear waters and stalactite and stalagmite formations in Nochoch nah Chich are not to be missed.

Dos Ojos – “Two Eyes” is one of the darlings of the Riviera Maya cave dive scene for some very good reasons. With two dive lines – one more challenging and one known for its wondrous light penetration – Dos Ojos caters to any experienced cave diver.

Gran Cenote – this world-famous cenote is the well-equipped entrance to the huge Sistema Sac Antun cave system. You might spot turtles as well as wonderful flora and geologic formations in this cenote’s excellent visibility.

Dos Pisos – “Two Floors” cenote has, just as its name implies, two tunnels along two distinct levels. One of these is far deeper than the other, necessitating even more advanced qualifications. But there are several sights in Dos Pisos which you simply have to see.

You can find out more about each of these fantastic Mexican dive locations in this article about the best cenotes for cave diving.

Just follow the line

Cave diving is perhaps the ultimate extreme sport. It takes skill, training and experience – not to mention the ability to stay calm under pressure – to succeed. It can be dangerous too. You need to be aware of your own limitations, always respect the safety rules and make sure that you dive with people who are properly qualified, responsible and who have the right training.

But it is the gateway to a subterranean world like no other. Giving you the ability to reach places and see sights which few other humans on Earth will ever get the chance to see.