Reserva Natural Las Cabezas de San Juan, Fajardo
Tel: 787 722 5882
Concierge.com's insider take:
This nature reserve about 35 miles east of San Juan is crisscrossed with wooden walkways that lead to mangrove forests and other ecosystems. One of the best walks takes you to a lovely colonial-era lighthouse. And if you can't make it to the bioluminescent bay on the nearby island of Vieques, there's one here that shines nearly as brightly. The only way to see the reserve is by joining a guided tour; call ahead for reservations.
Open Wednesdays through Sundays.