The Hot springs to Visit in Prats-Balaguer, France | Natural baths
- Nature Source Chaude
- Published on
- Updated on 4 May 2025
Over the course of history, some admirable sources have achieved great fame. Some are famous, while others are no longer so, or will not be until later. One of them, once little known, has, in the last twenty years, achieved a certain fame, which even extends beyond our borders. But nothing predestined it for such a fate.
Gushing in a wild setting on a mountainside, the wild hot spring of Prats-Balaguer in the Pyrenees can only be reached after a twenty-minute walk from a hill that must first be reached on foot.
Outside the summer season, it is sometimes necessary to brave the fierce winds of the Canigou, which defend access, in order to bathe.
For a long time, this spring was known only to the locals, until the advent of the Internet. Today, this sulphurous spring attracts insiders, adventurers and outsiders all year round. Let’s take a closer look at this enchanting spot on the heights of Fontpédrouse, near the hamlet of Prats-Balaguer.
N.B.: a hot spring is a complex environment, considered to be one of the richest on the planet in terms of biodiversity (micro-organisms). This article is intended to make you more aware of this.
IN SUMMARY :
The Prats-Balaguer sulphurous spring and its natural emergence
I had to reach this sulphurous spring by taking a path that starts at the top of a hill bordering the road (location given at the end of the article).
From the hill I walked to the right and took a path down to a stream.
Having crossed it, I followed a well-beaten path before coming face to face with a sulphurous, generous and boiling spring. This was the encounter between a man with a tired body and soothing, regenerating waters.
Then I smelled a slight smell of rotten eggs, which quickly faded. It’s not very intense compared to some sulphurous springs in Italy.
After a long long journey underground, the water springs naturally from a slope in the open air.
The fact that the source is not captured means that the environmental conditions for the micro-organisms that develop there are not significantly altered. These micro-organisms are present in all environments, such as water and air, but also in particular in the soil.
The thermal water gushes out at a temperature of almost 69 degrees, while the fire here is invisible. It is one of the hottest springs in the Pyrenees.
The distribution of micro-organisms throughout the site is controlled by water temperature and pH.
Water temperature has a major influence on the composition of this whole ecosystem.
But which ecosystem exactly are we talking about? This term refers to the myriad of micro-organisms present in the soil and water, most of which are invisible to the naked eye. They are so important that they are an integral part of the hot spring. They can be found in the pools, under the pools, and between the pools, through the various flow canals. But don’t panic! A wide variety and abundance of micro-organisms symbolise a healthy, living environment. They even make up the microbiota of the sulphur spring. To find out more about this, read the article ‘The soil, base layer and living medium of a hot spring‘.
A journey through the bowels of the Earth
A wide variety of micro-organisms (bacteria, cyanobacteria, archaea, yeasts, etc.) and a certain taxonomic richness are present from the moment the spring emerges and
However, other micro-organisms coexist with this source, long before it becomes visible on the surface. It is estimated that around 70% of the bacteria and archaea currently living on Earth actually live underground. The sulphurous spring at Prats-Balaguer, with a temperature of 69 degrees, is thought to come from a reservoir 2,000 or even 2,500 metres below the surface. And guess what? We now know that bacteria and archaea live at depths of up to 5,000 metres.
This abundance of life in the bowels of the Earth is a real mystery to the scientific community. For a long time, this environment was considered sterile because of the extreme conditions to which living organisms are subjected: rock, heat and pressure. Yet beneath our feet lies a vast biosphere teeming with life.
In fact, it might be more accurate to say that the water of a hot spring carries with it, as it travels underground, the memory of the geological layers it has passed through and the micro-organisms it has encountered.
The flow canal of the Prats-Balaguer hot spring
I was able to take a closer look at the flow canal (see image 1) that follows the emergence of the thermal spring. Even before taking a bath, I realised that I was inhaling vapours and gases with unsuspected benefits. To find out more about the benefits of thermal gases on the lungs, I invite you to read the article ‘How to cleanse your lungs with simple, natural ways’.
This canal consists of earth and a few rocks. But on closer inspection I noticed that several mats of ochre, brown and purple vegetation had developed. The green vegetation is more subtle.
The micro-organisms present on these vegetation mats are probably cyanobacteria, whose colours (blue, yellow, green, black, brown, purple, etc.) can vary according to the species (there are more than 7,500).
These cyanobacteria sometimes get a bad press because some species can be potentially toxic. While others are considered ‘superfoods’!
You may have heard of spirulina, a food with some extraordinary properties. It’s a seaweed. This algae from the cyanobacteria family is highly prized for its high concentration of nutrients. But it grows best in warm, mineral-rich waters.
In fact, sulphurous water is an ideal environment for the development of micro-organisms such as specific cyanobacteria. Note that cyanobacteria are bacteria, but they are related to algae.
These micro-organisms, which are visible on ‘vegetation mats’, have a higher degree of organisation than bacteria. The mineral salts and organic matter dissolved in the water allow them to live and develop, making it impossible for other cyanobacteria to proliferate. Other factors such as aeration and light also influence their development. They are classified as ‘photosynthetic bacteria‘.
A steep access path to the hot pools
By moving a few tens of metres away from the emergence, I was able to observe a more mineral flow canal this time (see image 2). The nature of the substrate (rock) can also influence the diversity of bacterial communities. Here the water is not as warm.
This temperature favours the development of emerald green or violet vegetation, which can be seen on some of the rocks. I was amazed by the variety of colours. These cyanobacteria are part of a thermal plankton that plays an active role in maintaining the quality of the water by secreting various substances (anti-inflammatories, hormonal substances, vitamins, enzymes, etc.).
But these cyanobacteria are only a tiny fraction of the microorganisms present in the hot spring.
Most of them live in the soil. It is difficult to see them because the soil is opaque and it is impossible to see through it. These various soil microbial communities self-regulate and regulate the micro-organisms in the water (cyanobacteria, bacteria, archaea, etc.).
If you can’t see them directly, you can only perceive the smell of earth and moisture wafting through the air. In fact, the smell is reminiscent of soil after rain.
I approached the first pool.
The slope is sometimes slippery because of the stones that roll under the shoes. The long flow canal (around fifty metres) that separates the emergence of the spring from the rock pool has cooled the water by around twenty degrees.
This first shallow pool reaches a temperature of around 45 degrees.
The trickle of warm water over living soil (the movement of the water alone is not enough) allows the water to maintain its vitality and properties, and above all to be enriched with various beneficial substances along its journey, despite the fact that it cools down.
When the soil is natural, the minerals and trace elements in the water are more likely to be absorbed by the body.
The wild setting of the Prats-Balaguer hot springs
The natural environment of this site makes this hot spring truly unique. Large stones hold back the water in a dozen pools arranged on the mountainside.
The thermal pools are shallow. This allows the water to be constantly aerated by the constant movement of the thermal water. This movement is almost imperceptible.
Each pool is continuously fed by one or more flow channels, which encourages exchange.
The Prats-Balaguer hot spring is located in a forest that serves as a natural backdrop.
Leaves, branches, twigs and dead insects are a good source of carbon (energy) for micro-organisms on the forest floor and in the sulphur spring.
The pools are clean and contain no visible plant waste. This is a sign of intense biological activity, thanks to the enzymes produced by the micro-organisms that naturally break down organic matter.
Finally, each pool is home to a wide variety of micro-organisms specific to its habitat.
The conditions under which the different microbial communities present in a pool develop vary according to changes in temperature, mineral salt concentration and the amount of light. Differences in pH and temperature from one side of the pool to the other can alter this complex ecosystem.
All these micro-organisms, present in the soil and water, have a major influence on water chemistry, even though they are invisible.
The nine pools offer each bather nine different experiences in thermal water with slightly different properties.
Finally, whatever its mineral composition, the high temperature of the water also makes it a valuable remedy. To find out more, please read the article ‘The amazing health benefits of a hot bath‘.
A second hot water source
A second hot spring is close by. It is partly hidden by the vegetation.
After following a footpath from the pool where the waterfall forms, a few dozen metres further on you’ll find a drinking trough protected by a low stone wall.
This sulphurous hot water fountain has a temperature of over 50°C.
How to get to the Prats-Balaguer hot springs?
To reach this place of peace, hot springs, trees and fresh air, take the D28 from the village of Fontpédrouse. Follow the road on foot towards the hamlet of Prats-Balaguer until you come to a bend in the road where you will find the access road to the springs (see location on our map).
The municipality recently placed large boulders on this bend (where vehicles used to park) and along part of the road to prevent vehicles from parking there. Since then the place is much less frequented, which is a good thing.
You should therefore reach this “bend” on foot, leaving your car behind:
– At the Bains de Saint-Thomas car park;
– At the Fontpédrouse car park (then walk back up).
– In the village of Prats-Balaguer (limited parking).
This unspoilt landscape is essential to the ecological balance of the area, which can flourish in complete freedom. However, this place of regeneration remains fragile if the rules of common sense are not respected.
It goes without saying that certain rules must be observed: litter must be collected, the site must not be degraded, inappropriate behaviour must be avoided, and so on.
Above all, people come to the baths to rest their minds, recharge their batteries and take a step back from everyday life.
To find out more about the nature of these waters and their properties, please read the article ‘ Wild hot springs in the Pyrénées-Orientales ’.
