Río Celeste: The Bluest River in Costa Rica

Río Celeste means "sky-blue river," and the name is the literal truth. Two clear rivers meet inside Tenorio Volcano National Park, and where they join, the water turns a milky, fluorescent turquoise. It's a real chemical reaction (minerals scattering light, not dye), and it's the kind of thing you have to see in person to believe.

It's about an hour's drive west from Casa Venado through some of the prettiest backroads in the country. Plan for a full half-day.

The hike

The main loop is about 6 km / 4 miles round trip on a well-maintained trail with some stairs and uneven sections. Most people take 3 to 4 hours. You'll pass:

• The waterfall lookout — a steep set of stairs down to a viewing platform over the turquoise falls. This is the photo everyone has seen. • The blue lagoon and hot springs — bubbling, mineral-rich pools along the trail. • Los Teñideros — the actual spot where the two rivers meet and the water changes color. Easy to miss; look down.

Tickets, hours & timing

Entry is about $12 for foreigners and must be booked online in advance through SINAC (the park system). The park caps daily entries and walk-ups are usually turned away.

Open 8 AM to 2 PM (last entry). Aim to arrive at opening — the trail is cooler, the river is more vivid in morning light, and you'll beat the tour buses out of La Fortuna.

What to bring

Hiking shoes or trail runners with grip (the trail gets slick and muddy after rain), a rain jacket year-round, water, and snacks. There's no food inside the park — eat before, or pick up lunch in the town of Bijagua on the way back.

When NOT to go

After heavy rain — usually October — the river can turn brown for a day or two because of sediment. If it's been pouring for days, check recent visitor photos on Google before driving over.

It's the most photographed spot in this part of Costa Rica for a reason. Go early, take your time, and stop for lunch on the way home.