Charco Frio, Rio Sabana
Charco Frío is a river pool on the Río Sabana at the eastern edge of El Yunque, and it is what Puerto Rican families use rather than the ticketed forest attractions. A short walk through forest from the roadside leads to a deep clear pool with rock ledges around it, cold enough to be a shock after the coast. There are no facilities, no lifeguards and no signage of any note - it is a local spot, and it should be treated as one: take rubbish out, park considerately. Critically, do not go in or after heavy rain. Mountain rivers here rise fast and flash flooding is the real hazard.