The thrill of cave diving in Mexico

Plunging over 30m into near-darkness through a murky cloud of hydrogen sulphide, James Henderson explores the eerie underground world of the Yucatán Peninsula

A diver at Chac Mool cenote in the Riviera Maya area of Mexico’s Yucatán
A diver at Chac Mool cenote in the Riviera Maya area of Mexico’s Yucatán Peninsula | Image: Getty Images/Stocktrek Images

Divers like to be so imperturbable and even‑handed that they’re reluctant to acknowledge a “best dive” sometimes. I suppose they dislike extremes of reaction. But I’m happy to hold up my hand on this one. Diving Angelita, one of the many cenotes of Mexico’s Yucatán Peninsula, was truly exceptional. Well, I think it was – it’s hard to be sure in the delicious and stupefying fug of nitrogen narcosis… But, yes, probably one of the coolest things I have ever done.

Cenotes certainly make for novel scuba diving. Set inland, the water is fresh and so visibility is fantastic – hundreds of feet in places – but then they are caverns. So while you’re never entirely out of sight of natural light – well, that’s the theory, anyway – you are underground. And this gives the activity a certain, er, thrill.


It’s a long old haul from the UK to Mexico, but if you take Friday off the flights work well enough for an extended weekend. There are flying restrictions, too, after diving, so you get a long, hard-working Saturday, followed by enforced relaxation on Sunday while you fizz out.

As we slide under the airbridge at Gatwick and lift off for Cancún, I read up on the Yucatán Peninsula. It is a vast chunk of sedimentary and coral limestone laced with underground cave systems. Over the ice ages, with the rise and fall of the sea level, they were flushed with rainwater, which (as dilute carbonic acid) dissolves the limestone, gradually eroding channels into underground rivers, but then also regenerating them with mineral deposits, stalactites and stalagmites. Today, the sea level is high, creating a saltwater pressure wall offshore, and the caverns are flooded. The cenotes are collapsed rock domes, sinkholes in the jungle, which provide entrances to the caverns (and, by the by, to the Mayan underworld).

Author James
Author James Henderson | Image: James Henderson


On arrival I am met by Matteo, and we drive 45 minutes south to Playa del Carmen and the cenotes. En route he checks what equipment I need and gives the beginnings of a briefing. I get nervous just thinking about it. Surely anyone with even a remote sense of self-preservation has some apprehension about scuba diving underground. And the thrill? Actually, make that terror. What if? What if? What of claustrophobia? And just plain old panic?


My hotel, Esencia, sits on a lovely bay of white (coral limestone) sand, its rooms strategically positioned in the rainforest behind. Dinner overlooks the garden. I try a cactus salad, which turns out not dissimilar to broad beans – and, sadly, similarly distasteful to me. Early to bed.



The good thing about travelling this way around the world is that I am up early, refreshed. Soon after dawn we head south to Tulum, where the sun rises over the famous Mayan city on the Caribbean coastline.

Diving profiles dictate that the first dive in a long day is the deep one; so we head for Angelita. There, Luis, our dive leader, walks us through the forest to the cenote to take a look – an ambulatory briefing, if you like. It is an almost perfect cylinder, 60m across, its rock ledges sprouting with jungle trees. The water, a rich royal blue, is incredibly inviting.


Usually, rigging up is a haphazard struggle against the roll of a boat, but here we put on wetsuits and tanks in a rainforest picnic area surrounded by squawking birds and “chicle” rubber trees, complete with angled cut marks to bleed the chewing gum. In our full kit, we tramp back to the cenote. Fins on, we lob ourselves off a 2m ledge into the water.

As I look down, the inviting royal blue becomes a threatening gloom. Clearly my eyes are like cartoon dinner plates: with care and resolve in equal measure, Luis allays my fears and we descend into the muted watery silence, which is broken only by the hiss and gurgle of my breathing.

Some of the
cenotes, such as Aktun Ha, feature dramatic rock formations
Some of the cenotes, such as Aktun Ha, feature dramatic rock formations | Image: Getty Images/WaterFrame RM

At 15m down, a very strange sight appears – a small section of land partially protruding from a grainy brown layer of what looks like sand. The “sand” is, in fact, hydrogen sulphide, swirled around like light-brown stucco. At 30m, the three of us face one another again. Luis gives me the diver’s “OK?” and a thumbs-down (for downwards)… I’ve just got to do it. I signal OK in return with my thumb and forefinger, and, biting my mouthpiece hard, I slide down through the opaque brown sulphide – I taste it on my regulator – and emerge into the darkness of the saltwater below.

Very little light penetrates down here. Torchlight reveals a ghostly scene of broken trees, lifeless trunks and branches, and stones in sediment. The ancient coral rock walls close in, pitted and scarred. We follow the mounded island around – quite quickly, as my air is disappearing fast, breathing nervously at 33m. Then a moment of magic arrives as I rise slowly through the sulphide layer and emerge into a surreal painting: an agonised tree on an island, an eye-level sweep of beige, like windswept sand, and the scratchy blue gloaming of the freshwater. Sunlight spangles from above.


At Dos Ojos, our second cenote, Matteo has laid on a picnic, so we pause for a bit.

If Angelita was a descent into ominous blue gloom, here is another challenge – a proper cavern. Years of diving in open sea makes enclosed space feel unnatural. And, frankly, pretty scary. Once again, Luis cottons on quickly; he bluffs me and down we go again.

Ascending into the light
Ascending into the light | Image: Getty Images/Stocktrek Images

Under the lip, and suddenly we’re suspended in another world, moving in single file, past jumbled rocks and gaping recesses. It is disorienting and increasingly dark, so again we explore by torchlight. Stumpy stalagmites sit on the floor like pimples, while stalactites stretch down towards them. In places, they join. We weave between columns as thick and muscular as thighs. Other formations are curled and furled, flash-frozen waterfalls of white chocolate. Yellow leaves hover all around.

In the cave, a partly flooded chamber, we surface to the squeak of bats flitting among the filigree tree roots searching for water and crawling into the ceiling folds. And finally, back underwater in the depths of the cavern, at Luis’s suggestion, we switch off the torches. Looking in one direction the darkness is total. But 20 yards away in the other is a cave entrance, shining luminously behind a curtain of light, shards penetrating from above.


At Tajma Ha, there is no one else around; so before our third dive, we take a dip and chat. These caves are still being discovered and explored. While they were dry during the last ice age, animals found their way in there, until around 8,000 years ago when the sea level rose again. Recently, the fang of a sabre-toothed tiger was found, and the skeleton of an extinct species of llama. (Luis was involved with recovering the second-oldest human skeleton in the Americas.)

Tajma Ha is another cavern dive, but it also illustrates well both the saltwater and freshwater provenance of these systems. Deep in its recesses are massive fossilised shells – outsize conchs embedded in the rock. Above, 30cm-long needle stalactites protrude from the ceiling; I am inside a massive pin-cushion. Then we emerge into a partially filled “dome”. Below, the waterline light diffuses in a colourful prism. Above, through a small hole in the roof, a shaft of sunlight is shining like a laser.

Divers at the entrance of Kukulcan cenote
Divers at the entrance of Kukulcan cenote | Image: Getty Images

But Tajma Ha is best known for its halocline, where freshwater sits on saltwater. The divide is unexpectedly sudden – a clear line shimmering like oil on water – and visible within the span of a mask, just slightly disjointed as the light refracts differently through each liquid. But I am about to get a surprise. Luis leads us on, through the narrow entrance to another cavern. As I am halfway through, he gives a teasing kick with his fin. Instantaneously, the water is a hazy opaque mush, pixelated like a child’s kaleidoscope. I cannot see a thing.


I feel fantastic, somewhat relieved to have survived but very pleasantly weary. Esencia is a delight. I sit in my jungle suite, listening to tree frogs sing for joy in the evening cool. After some elegant tacos, I head off to bed.


I have found my way onto Mexican time and ahead of me lies a compulsory lazy day on the beach. Nothing wrong with that. In the heat the slightly stupid euphoria and dreamy satisfaction sustain. I lift off for London in the late afternoon.



After another sleep of Lethe, I arrive safe and sound back at Gatwick. But, still befuddled, I find the weekend rather hard to compute. I was panicked, then relieved and definitely narked; but hanging a hundred feet down in Angelita really was a sight worthy of Dalí. And then the haloclines and beige sulphides… yes, definitely, too cool for words.

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