What to expect
You descend a carved stone stairway into the cool, partly shaded sinkhole, where black catfish drift in the deep green water and roots hang from the limestone walls. Life jackets are required and available on site, and there are showers, lockers and a restaurant in the surrounding park.
The water is deep, so it suits confident swimmers; weaker swimmers should keep their life jacket on. Bring a quick-dry towel and reef-safe sunscreen only, applied after your swim, as the cenote bans regular sunscreen to protect the water.