La Fortuna Waterfall is a 70-metre cascade that drops into a clear emerald swimming hole surrounded by jungle. The hike down from the entrance is short but steep — about 500 steps each way — and the climb back out in the heat is strenuous. Go early, before the tour groups arrive, and you may have the pool to yourself for twenty minutes of cold, clear, spectacular swimming.
The entrance is about 5 km from La Fortuna town, reachable by taxi or on horseback (several operators offer a combined horse ride to the waterfall). The fee includes access to the trail and swimming area. Currents in the pool can be strong, particularly after heavy rain, and the rocky sides require care. There are changing facilities and a small café near the entrance. The waterfall is within the Arenal Volcano National Park system; some operators sell combined tickets.