Poás Volcano National Park, Alajuela, Costa Rica

Poás Volcano: Costa Rica's acid crater lake

Poás summit sits at 2,708 m, and its crater lake, Laguna Caliente, is one of the most acidic lakes on Earth, with a pH near 0. On a clear morning it glows turquoise from the lookout; on a foggy one you get a white wall, which is exactly what I got. Entry is timed and sold online only through SINAC, Costa Rica's national park system, so book the first slot of the day, since clouds usually roll in by mid-morning.

See the Instagram reel

Bookable experiences

• Viator

  Coffee Plantation, Poás Volcano and La Paz Waterfall Gardens

  from $185

  Poás crater, a coffee plantation and La Paz Waterfall Gardens with pickup in San José, about 10 hours, 4.9 (822 reviews)

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• Viator

  Poás Volcano, Waterfalls and Coffee Tour from San José

  from $149

  Poás crater, waterfalls and a coffee farm tour with pickup in San José, 8-10 hours, 4.8 (193 reviews)

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• GetYourGuide

  San José: Guided Volcano, Waterfall & Coffee Farm Day Trip

  from $139

  Guided day trip to Poás, a waterfall and a coffee farm with pickup in San José, 1 day, 4.7 (720 reviews)

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• GetYourGuide

  San José: Poás Volcano, La Paz Waterfall & Coffee Tasting

  from $105

  Poás crater, La Paz Waterfall and a coffee tasting with pickup in San José, 1 day, 4.4 (756 reviews)

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Prices may change, so check the dates before you book.