Humacao Nature Reserve
The recreational area of the Humacao Nature Reserve, also known as the Punta Santiago Natural Reserve, has six acres of flat, well-marked trails winding their way through a palm tree forest, mangroves, around lagoons, and onto the beach. Off the main trail there is one hill with a short steep climb called El Morrillo which offers a stunning view of the coast. At the reserve there are gazebos for picnics, bathroom facilities, free parking, you can go fishing, and you can rent bikes, paddleboards, or kayaks.
Cabo Rojo National Wildlife Refuge and Salt Flats
The Cabo Rojo National Wildlife Refuge is managed by US Fish and Wildlife Service and has a variety of hiking and biking trails. These are mostly flat, surrounded by a wide variety of dry forest plant life and native birds, with observation towers along the route. There are also trails around the bright pink salt flats, which create a stunning and surreal landscape. If you want to challenge yourself, follow the trails all the way to the jagged cliffs of Los Morrillos Lighthouse and beautiful Playuela Beach.
The visitor's center for the Wildlife Refuge is open Monday through Saturday, while the Cabo Rojo Salt Flats visitor's center is open Thursday to Sunday. Make sure to have sturdy footwear with thick soles and clothing that's appropriate for hot weather, wear sunscreen and a hat, and bring plenty of water and food since most of the trail is very exposed.
Hacienda La Esperanza Nature Reserve
This extremely varied natural reserve has half a dozen different ecosystems within it: wetland, grassland, karst hills, mangroves, an estuary, and beaches. The property at Hacienda La Esperanza, which includes a historic and very well-maintained sugar mill, is managed by conservation organization Para La Naturaleza. Their visitor's center is a manor house which is part museum and part education center. To visit the hacienda, reserve a tour with Para La Naturaleza, most of which involve a guided hike through the property.
If you'd rather do your own hike, follow the road where the visitors center is located to the end. There will be a gate and a trailhead. You can park on the side of the street (at your own risk!) and hike the trail all the way to Esperanza Beach, a lovely secluded beach with shallow waters and large volcanic rock formations. If you continue down that trail, you'll reach a second beach with black sand. These hikes are easy and the trails are well-marked, just be sure to bring water and food, sunscreen, hats, and a bathing suit.