Cenote Cristalino

Half of Cristalino lies in the open among mangrove and the rest runs back under a limestone shelf, so you can swim from sunlight into something that feels like a cave without needing any gear. Divers go further, into a flooded cave system that starts here.

There is a platform about three metres high for jumping, and benches around the edge, some of them half under water. Lifeguards watch the pool, life jackets are handed out, lockers can be rented and a small kitchen sells snacks. It is built to handle crowds and it gets them, so arrive within half an hour of opening for a quiet swim. Wear water shoes on the slippery rock. Jardín del Edén is next door if you want a second cenote the same day.