It’s called Río Celeste for a reason.
Tenorio Volcano National Park is home to this stunning waterfall and vivid blue river. The water is so blue, you’ll think your eyes are playing tricks on you.
Suspended particles in one river called alumino-silicates collide with another river, laying down a visible line of white sediment at the bottom of the confluence. But just downstream, these same sediments float into the current at just the right size and with just the right chemical properties to reflect the spectrum of the sun in only blue — giving this river its spectacular color.
Be forewarned that the river may be muddy and brown when you arrive. The best time of year to see Río Celeste actually celeste is December through April, the so-called dry season, but be advised that it rains here cuando Dios quiere, and the river may be blue or brown at any time.