Termales Río Celeste

Insider tip — Rio Celeste is world-famous for its otherworldly turquoise color, caused by nanoparticles formed when volcanic sulfur combines with the river's mineral load flowing off Tenorio Volcano. The thermal area sits at the river's headwaters within Tenorio Volcano National Park, where hot sulfurous vents keep sections of the river warm year-round. Swimming is prohibited in the national park itself to preserve the fragile chemistry, but adjacent thermal resorts channel the geothermal water into purpose-built pools with views of the cerulean river. Book accommodation in Bijagua to hear howler monkeys at dawn and walk jungle trails before the day-trippers arrive.