The Cuzama cenotes are one of the better-known swimming day trips southeast of Merida. The classic circuit links several cave cenotes with clear, cool water, and part of the old charm is the small truck-and-rail-cart system once used for henequen work.
Conditions and operators can vary, so ask locally before choosing a route and be thoughtful about animal welfare where horse-drawn carts are involved. The cenotes themselves are the reason to go: dark openings, blue water, and a sudden coolness that feels wonderful in the Yucatan heat.