The color of Rio Celeste

Visit Rio Celeste lies at the foot of the majestic Tenorio volcano in the heart of the Tenorio National Park. Let's take a quick tour of the region. Located in the heart of Tenorio National Park, Rio Celeste is a jewel in the rainforest.

The sky-blue color of the Rio Celeste?

Let's get to the heart of the matter and answer THE question asked by every traveller who has ever had the chance to see the phenomenon up close. For those who haven't (yet) experienced it, let's summarize the picture: The Rio Celeste river lies in the middle of a dense, deep-green rainforest and, depending on the weather (we'll see why this is so important) offers a brilliant sky-blue color in some parts of its course.

So where does the blue color of the Rio Celeste come from?

For many years, local guides, specialists and geologists have explained that the river's blue color comes from the emanation of certain gases at a site called "Teñidero", accessible via one of the trails in Tenorio National Park. This "coloured" area is only present over a distance of around 14 km. Until now, it had been thought that the color came from a high concentration of copper, calcium carbonate and sulfur. However, there had never been any certainty as to the real reasons for this transformation at this precise location (Teñidero).

The legend

Local residents love to tell this story. According to them, God washed his brushes in the river after painting the sky blue. And, in a way, they weren't far off the mark, for the blue color of the sky does have a role to play in the final process.

Where does its blue color come from?

So what's the real reason? In 2013, a small group of researchers from the University of Costa Rica decided to crack the secret. After several analyses on the Rio Celeste, Quebrada Agia and Río Buena Vista rivers, the first unknown presented itself. Why was the water a turquoise color when sampled, but completely transparent in the laboratory? Faced with this enigma, the scientists returned to the field to consider other factors. They realized that in the Teñidero area, there was a "whitish" substance present in the water. This substance, composed of several minerals - aluminium, silica and oxygen - is called aluminosilicate. The colors of the light spectrum arriving in the waters of the Rio Celeste are practically all absorbed, except for the bluish colors, which are reflected, giving us this superb spectacle. So why isn't this color present throughout the river? It's a question of the size of the whitish particles that cover the river bed. The particles in the Buena Vista River are 186 nanometres in size, while those in the Rio Celeste River average 566 nanometres. And it's precisely this difference that allows the blue spectrum to be reflected. That's why you'll be able to observe the phenomenon magnified by fine weather and a beautiful blue sky. The light blue of the sky will be more easily reflected by the minerals in the river.

Tenorio National Park

Created in 1955, Tenorio National Park is part of the Arenal-Tempisque conservation area. It covers just over 18,402 hectares of tropical forest and volcanic land. It is best known for being home to two natural treasures: the Tenorio volcano and the Rio Celeste river. Opening hours: Open daily from 8:00 am to 2:00 pm, but you can stay until 4:00 pm. Rates : Nationals: ¢800. Foreign: $USD 12  

Tenorio volcano

It is a stratovolcano with a height of 1916m. It has five craters and is currently inactive. Its main crater is now a lake surrounded by tropical forest. There are several thermal springs on its flanks, including one on the banks of the Rio Celeste.  

The Rio Celeste

  Originating from the confluence of the Agria and Buena Vista rivers, the Rio Celeste is best known for its celestial-blue color. Its main attractions, apart from its color, are its waterfall, the Teñidero site that gives it its particular color, the observation points on the Tenorio volcano, the thermal waters, the small sky-blue lagoon and the tropical forest that surrounds it. There are two ways to visit Tenorio National Park:

• By Bijagua
• By Guatuso, Katira

How to get there

By car, from San José, take the General Cañas highway towards Puntarenas. Continue on the Interamericana to the town of Cañas. After about 10 km, turn right and continue to the village of Bijagua. Once in Bijagua, head east past the large sawmill (approx. 9km).   If you'd like to visit Tenorio, why not discover it on one of our itineraries ?