Ribeirão do Meio is a series of natural waterslides and pools on the Ribeirão river about 6 kilometres from Lençóis, one of the best swimming spots in the park and among the most popular day trips from town. The river has carved a smooth channel through the quartzite rock, creating a series of natural slides that deposit swimmers into deep, crystal-clear pools of chilly water.
The walk from Lençóis takes about two hours through low cerrado vegetation with good views of the surrounding mesas. The main waterslide — about 10 metres of smooth, curved rock — is straightforward to descend with proper technique (you go feet-first, sitting upright) and the pool below is deep enough for safety. The upstream pools are calmer and suitable for children. This is an excellent introduction to the park's combination of geological spectacle and natural swimming, and it requires no guide — though taking one provides navigational confidence and natural history context.