The only remaining rivers in Costa Rica that often run clear to the sea flow on the Osa Peninsula in areas with rugged terrain, like the R?o Agujas in Drake Bay or the R?o Claro at Punta Marenco. Follow the coral if you want to find the clear water away from river mouths.

For the clearest water in Costa Rica in 2026, you should head to the southern Pacific coast, specifically Caño Island Biological Reserve. Located off the Osa Peninsula, this area offers visibility often exceeding 80 feet, making it the premier destination for snorkeling and diving. On the mainland, the Guanacaste region (North Pacific) also boasts very clear waters in sheltered spots like the Gulf of Papagayo. If you prefer the Caribbean side, Cahuita National Park and Manzanillo offer stunning turquoise clarity, but this is highly dependent on the season; during the "mini dry season" in September and October, the Caribbean water is at its most crystalline. For a truly remote and pristine experience, the volcanic Catalina Islands offer exceptional clarity and a high chance of spotting giant manta rays.