Floating Down an Underground, Secret River in Mexico

Rio Secreto, underwater cave near Cancun, Mexico

Listen… (ooo, waa, ooo) …do you want to know a secret?

Okay seriously, with apologies to The Beatles, the Yucatan Peninsula is hiding miles and miles of secret rivers.

This was revealed to us just outside the Riviera Maya town of Playa del Carmen, Mexico when we descended beneath the surface and into Rio Secreto.

By into, we really mean in to.

Rio Secreto, underwater cave near Playa del Carmen, Mexico

Allow us to explain about this most unique spelunking experience.

Although the cave is ancient, it wasn’t discovered until 2006 when the property owner chased an iguana into a hole and heard a splash.

Curious, he dug a bigger opening and happened upon over twelve kilometers of underground river flowing to the Caribbean Sea. After a couple of years of work mapping and exploring, he decided to open the amazing tunnels to the public–as long as precautions were taken to protect it.

Rio Secreto, underwater cave near Playa del Carmen, Mexico

We are by no means experts when it comes to cave explorations — yes we have been down a hole or two (both literally and figuratively) — but never anything remotely close to this.

Certainly not any that required donning a wetsuit. Yet even in the tropical Yucatan jungle we were sure glad we suited up, the water in this underground stream never sees the sun so it is cool enough that skinny dipping was hardly an option.

Right, let’s pretend that is why we don’t skinny dip anymore.

Once we had wriggled into our second skins, we showered to make certain no chemicals from sunscreen or makeup could contaminate the pristine system below us.

The wonder of Rio Secreto in Playa del Carmen, Mexico! GypsyNester.com

This is just one of the many precautions Rio Secreto’s operators take to ensure the protection of the fragile formations and wildlife that occupy the cave.

Everyone involved with these tours views this as an ecological preserve, so the goal is not only to introduce this amazing underworld to people, but to conserve it for the future.

In addition, we were issued water shoes and a life vest, so that we could effortlessly drift along.

Lastly, we were fitted with an ultra-cool, light-weight, modern version of the old miner’s helmet. Our new-fangled head gear came with super bright LED lights.

Later we would learn what the cave would be like without those lights. Let’s just say that we would still be down there because we would never have found our way out.

The ceremonial blessing honoring the Mayan traditions of rebirth before entering Rio Secreto in Mexico! GypsyNester.com

As much as the attire was appreciated once we were in the water, it wasn’t high on our list of desirable outfits for trekking above ground.

Luckily that part of the journey was short. We walked a few hundred meters to the cave entrance and stopped for a ceremonial blessing honoring the Mayan traditions of rebirth associated with entering and exiting these sacred sources of life-sustaining liquid.

David hikes down into the depths of Rio Secreto near Cancun, Mexico! GypsyNester.com

With our respects paid to the ancient traditions, our guide Paulo led us down into the darkness below. Our first discussion centered on how the cave and its features — the stalactites and stalagmites —  were formed.

All of the land on this part of the Yucatan Peninsula is made of limestone, which at one time was an ancient coral reef. In fact, much of the walls of the cave still look like coral.

The limestone dissolves fairly easily, so the heavy tropical rains have carved out many of these long underground rivers, and even more cenotes, which are large, water-filled sinkholes.

These were incredibly important as water sources for the Mayans, and are still supplying drinking water today. Yet another reason for protecting the river from contaminants.

Dripping water in Rio Secreto Mexico

As for the classic cave features, stalactites and stalagmites, Paulo explained how they form over many years by dripping water.

As the water seeps through the stone it picks up calcium, which is then deposited little by little, leaving layers that create the eerie cones called stalactites that hang from the top of the cave.

When the drips fall, they form the matching rising cone shapes on the cave floor known as stalagmites.

There are a few tricks to remembering which is which; Paulo’s was that the T in stalactite stands for top, an old geology teacher told us “stalactites stick tight.” It worked, we still remember it.

Dripping water in Rio Secreto Mexico

After enough time, the two will meet with “a kiss” to form what is known as a column.

See all of our adventures in Mexico!

Sometimes other forces, such as the capillary action of water being drawn along against gravity the same way a wick works, or changes in water levels, or wind can act on the formations to create strange and wonderful variations.

These cave features, known as speleothems, will appear as straws, which form when drops fall and leave a tiny ring behind, or curtains, which come from water slowly running down a slope.

Perfectly smooth gems known as cave pearls, which occur as drops roll a small stone in a pool in Rio Secreto, Mexico

Even rarer are helictites, which grow out like branches or fingers and seem to defy gravity, or the perfectly smooth gems known as cave pearls, which occur as drops roll a small stone in a pool.

Incredibly, every one of these was present in Rio Secreto.

Roots from the trees in the jungle above work their way down to the water of Rio Secreto in Mexico

We noticed another extremely interesting feature protruding from the ceiling of the cave, roots.

No plants can grow in the environment of total darkness, but roots from the trees dozens, sometimes even hundreds, of feet above have pushed their way through the stone in search of the precious water below.

The force and determination involved is truly amazing, and yet another example of life always finding a way to forge ahead.

See all of our adventures in Mexico!

In keeping with that phenomenon, a few animals have managed to adapt to the lack of any light.

Bats hanging around Rio Secreto near Cancun, Mexico

Cave spider at Rio Secreto near Playa del Carmen, Mexico

Bats, well-known cave dwellers, are fairly plentiful, especially near the openings that give them access to the outside world.

But even deep inside there some hardy residents. Crickets, ants, and a spider that has developed sensitive, antenna-like front legs for “seeing” in the dark, have all found a way to manage living deep underground.

A blind catfish in Rio Secreto near Cancun, Mexico

Two types of fish, a small catfish, and the blind, colorless cave fish, inhabit the waters.

Paulo was very excited that we spotted both with our headlamps, since the cave fish are very rare indeed. The little white fish are not only blind, but over the eons they have completely lost their eyes.

No need for them, so they simply don’t grow any.

Floating down Rio Secreto in Playa del Carmen, Mexico

David swims through a tiny hole in Rio Secreto in Playa del Carmen, Mexico! GypsyNester.com

A little over halfway through the cave the water began to get deeper. Up until that point we had been anywhere from ankle to waist deep, but we would have to swim for it to go on.

Float for it might be more accurate, which was great. We rolled over on our backs, and down a lazy river we went, awestruck the entire way.

David floats down Rio Secreto in Playa del Carmen, Mexico! GypsyNester.com

Sitting in Rio Secreto before we turned our headlights out and put in total darkness! GypsyNester.com

When we reached another shallow section, Paulo sat us down and introduced us to something most people have never experienced, total darkness.

We may think we have been in the dark, but no, there is almost always at least some tiny light source that our eyes can pick up and begin adjusting to.

Not this time. The complete, utter, absolute, unquestionable … okay, okay, point made, absence of any light whatsoever brought on a strange sensory deprivation that was somewhat unnerving. If we hadn’t known that we had the option to turn on our lights we probably would have freaked out.

Camera flash in Rio Secreto looks like fireworks

Then a camera flash slashed through the darkness and shocked our vision.

Wow! It was so intense that we could see the bright outlines of the stalactites for several seconds. Paulo did it again, then again, and it was like a fireworks show inside our eyeballs.

Had to take the goofy pic at Rio Secreto in Mexico! GypsyNester.com

There wasn’t going to be any topping that sensation, so with our lights back on, and our vision restored, we made our way up to the surface once again.

Back above ground we slithered out of our wetsuits and took a quick walk through the dry portion of the cave. This is an easy alternate route for those spelunkers who might not be comfortable with the total immersion version.

Best of all, it led to a mouthwatering buffet of local favorites.

Who knew spelunking could work up such an appetite?

David & Veronica, GypsyNester.com

We visited Rio Secreto while attending TBEX in Cancun, Mexico!

See all of our adventures in Mexico!

YOUR turn: Isn’t it gorge-ous? Could YOU go down into an underwater cave in the total darkness?

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37 thoughts on “Floating Down an Underground, Secret River in Mexico”

  1. I picked this as my shore excursion when my April cruise stopped in Cozumel and it was hands down one of the most impressive I have been on!!! I wondered if I was going to have to deal with any claustrophobia issues, but honestly I was so engaged in every moment of the adventure that it was truly a non-issue. So visually striking and fascinating…I would go back in a heartbeat…I just can not say enough about the experience!!!

  2. Without seeing your photos, I’m not sure I would have said yes to this experience. I do get a bit claustrophobic! But now that I’ve seen the light-so to speak-this looks like an experience of a lifetime. So beautiful and your photos captured the light in many unusual ways. I was so sorry to have missed TBEX this time. I heard Cancun and just thought bikinis and cocktails. Look at how wrong I was. Won’t let that happen again.

  3. I’ve been in caves before, but none so beautiful! I love the photo of the bats what a great capture. That spider would have sent me running out of there faster than Speedy Gonzalez!

  4. Wow – I do love a great travel adventure as much as anyone, but I’m not sure this is one of them, especially seeing the one photo with the water rising. You’re a brave heart!

  5. So cool! You had me until I saw the 6 inches of clearance above your head at one point – I’m not claustrophobic normally, but that might get to me, especially with water below!

  6. We lived in Playa del Carmen for three months at the end of 2012 and visited several of the cenotes in the Yucatan area. Unfortunately, we dismissed the Rio Secreto as an expensive tourist trap and, after seeing your gorgeous photos and hearing about your amazing tour I want a “do-over!”

  7. Gosh – what a wonderful expedition – and how fantastic that they take contamination so seriously you have to shower again before entry – I love that kind of commitment to their precious environment 🙂

  8. I would’ve been afraid, but more angry with myself if I’d passed up the chance to do this. So yes, woulda instead of shoulda all the way for me. I loved the idea of honoring the pristine ecosystem and the ancient deities. Covers all the bases. Loved the vivid photos, too.

  9. Now this is one adventure I would love to have done. I’m with you on a possible freak-put if it was only black. What a strange feeling that would be.
    I’ve never floated in a cave – boated once in the Dordogne but this looks even better.

  10. I am really sorry I missed TBEX in Cancun and while I enjoyed reading your account of your wading/floating/spelunking adventure, I suspect my claustrophobia would have been in overdrive—-although I have survived a few cave expeditions. Nice photos, especially considering the light challenges.

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