Explore the Bassin Bleu lava tunnel

The Bassin Bleu lava tunnel

Explore the Bassin Bleu lava tunnel, the only one in the west of Reunion Island, created more than 400,000 years ago. At the antipodes of the lava route (East coast), discover a volcanic tunnel in the heart of the Eperon village, 10 minutes from Saint-Gilles.

Welcome at the Eperon village

A peine quelques mètres plus haut que le village artisanal de l’Eperon, connu pour ses petites boutiques, restaurants et marchés de créateurs, on rejoint Sébastien, notre moniteur, à 9h pour cette sortie 100% péi.

Une fois le groupe au complet, on s’équipe de tout le matériel nécessaire pour partir à la découverte des entrailles de notre île. Genouillères, gants, baudrier et bien sûr le casque avec frontale, sexy, sexy !

Once the group is complete, we equip ourselves with all the necessary equipment to explore the bowels of our island. Knee pads, gloves, harness and of course the helmet with frontal, sexy, sexy !

Blue Water (bassin bleu)… rather green!

Once well equipped, we’re ready for the 5-minute mini walk that takes us straight to Bassin Bleu (bleu water basin). So unlike the one in Saint-Anne, which bears its name very well, this one could have been called Bassin Vert (green water). But even if you don’t really want to swim there, the setting is great and having already done lava tunnels in the East, we did not expect to explore a tunnel in this type of setting.

Salanganes’ place

To access the tunnel’s entrance, we are very happy to have Sébastien, our guide but also his equipment. Indeed, you have to climb no less than 6 meters to reach “the cave”, the starting point of the tunnel. Many salanganes (birds) fly around the basin and as their nests are in the cave, they go back and forth in the tunnel. Once in it, some brush against us by a few centimeters!

The “salangane” is a species of bird endemic to the Mascarenes, very similar to the Bourbon swallow. But unlike the latter, they live in caves and almost always live in the air. In fact, their legs are so short that they rarely land, except to sleep and hatch their eggs. You will therefore have to share their sanctuary and make yourself as small as possible so as not to disturb them.

So let’s climb!

That’s it! One by one, we climb the wall to the cave’s entrance. Nothing too complicated, but we are happy to be assured with ropes. Once all at the top, we are ready to begin the visit of the tunnel.

This tunnel is part of the Ravine Saint-Gilles, one only west coast gully that is really active, with its famous 3 Trois Bassins (Malheur, Aigrettes and Cormorans).

We start in a somewhat narrow part before having more room to walk upright. We take several breaks so that Sébastien explains to us the different rock formations, the why and how of the different colors, etc… After a while we have to squat for a few meters to be able to progress. It’s a little tight, but even Romain, who tends not to feel super comfortable in confined spaces, gets by without worry.

Salanganes or bats?

We continue to progress in the Bassin Bleu lava tunnel and we go from discovery to discovery. Sébastien lights up the salanganes’ nest for a very brief second. If we didn’t know what species we were looking at, we’d think of bats. In the tunnel, they fly in “echolocation”, which means that they are directed by echoes, sound waves reflected on the cave’s walls.

To try to disturb them as little as possible, Sébastien asks us to walk, when possible, sometimes all to the right, sometimes all to the left to leave them a free corridor to move around.

Picnic room, cathedral, pizza oven…

We continue on our way in the dark… lit of course by our headlamps, our best friends in this total darkness. We discover rooms with equivocal names: the picnic table, the cathedral or even the pizza oven (a very small room in height through which we enter through a very small hole, and yes, we are the pizzas!). We also discover a lot of geological formations.

Small stalactites, lava benches or crumpled paper flows. There are also vast white and shiny walls. Sébastien explains that these are magnesite concretions and calcite stalactites. But we’re not going to spill the beans on you, we’ll leave it to you to find out for yourself!

Total black in the Bassin Bleu lava tunnel!

Once at the end of the tunnel, it’s time for a break. With the sound of running water, we all sit in a circle and Sébastien serves us our choice of a little coffee or a good local herbal tea. After a few minutes, we turn off all our headlamps and it’s total and absolute black.

And indeed, we see nothing, but then nothing at all! With zero light, the eye does not get used to it and you really cannot distinguish any form. Even moving my hand right under my eyes, nothing. It doesn’t sound so crazy, but it’s actually very rare to have total black. Another consequence of this penumbra, the other senses tend to be increased. The most striking thing are the noises that seem to get louder… For some people it could be unpleasant, but here it’s unanimous, it’s just pleasant and relaxing.

Return to the surface and zip line!

Once this unusual break is over, we turn around to end our journey in the opposite direction to exit the famous Bassin bleu lava tunnel. The return is done more quickly since we have already had most of Sebastien’s explanations. We will have done barely more than 1km underground and yet we had the impression of doing 3 times more! At the same time, sometimes crouching and in the dark, we progress so much slower!

For the exit, as a general rule it is the Grand Final with a zip line of about 30 meters above the Basin. But unfortunately Sebastien had had his equipment stolen the day before. But that’s only a postponement!

Never has an outing in the dark and on all fours been so fun! Between the unusual experience, the super enriching Sebastien’s explanations and good humor, you can go there with your eyes closed… with a headlamp of course!

Pratical Information for the Bassin Blue lava tunnel:

This Zarlor “Bassin Bleu Lava Tunnel” at L’Eperon usually starts between 8 and 9 a.m. and lasts around 3.5 hours. Then, you will go to lunch in Saint-Gilles!

The price is €66 for children over 12 years old and €60/-12 years old.

For all the details on this activity and to book your Zarlor Lava Tunnel, it’s on the website of the West Tourist Office.  

Don’t forget: pants, sneakers, water. This activity is accessible to people in good physical condition! (6m of climbing at the start and progression in the tunnel is sometimes done by crawling or kneeling). Also avoid it if you are prone to vertigo or claustrophobic!

And to find all our activities in Réunion, it’s this way !