A cenote is a natural sinkhole where limestone bedrock has collapsed to reveal groundwater below — sometimes open-air, sometimes a cave you swim into, always startlingly clear because it's filtered through rock rather than fed by rivers.
Where to find them
The Yucatán Peninsula sits on a vast network of them; the highest concentration reachable from Cancún is inland toward Valladolid, with a smaller cluster closer to Puerto Morelos. Most are on private or ejido (communal) land and charge a modest entry fee that supports the local community maintaining them.
Open vs. cave cenotes
Open cenotes feel like a jungle swimming hole with sky overhead; cave cenotes are partially or fully enclosed, often lit dramatically by a single shaft of light — stunning, but check comfort with enclosed spaces before booking a tour built around one.
Visiting responsibly
Most cenotes require a quick shower before entering and ban sunscreen or bug spray that isn't reef-/cenote-safe — the ecosystem is fragile and the water doesn't flush out the way a beach does. Bring reef-safe products or go without.