Cachoeira do Toboga is the best-known waterfall stop on the road inland from Paraty, famous for a smooth rock chute that locals use as a natural slide. It is not a wilderness escape, but it is a good, lively counterpoint to the cobbled historic centre and island boat trips.
Go with shoes that can handle wet stone and expect company on warm weekends. The waterfall is often combined with nearby distilleries and forest stops, which makes it an easy half-day if you want freshwater before returning to town.