Distinct from the Department of Natural and Environmental Resources (DRNA) state forest system, these coastal and marine reserves protect some of the island’s most scenic – and most photographed – shoreline and watering holes.

Nature Reserve

Municipality

Region

Why It’s Popular

Access Points, Trailheads & Swimming Holes

Río Camuy Cave Park

Camuy / Hatillo

North

A striking karst region with one of the largest cave systems in the Western Hemisphere, carved by an underground river.

Main entrance at PR-129, Km 20, Bo. Quebrada, Camuy; the paved Cueva Clara de Empalme show-cave walkway is the main visitor route. No swimming hole on site — this is a cave-tour park, not a river-swimming destination.

Isla Mona Nature Reserve

Mayagüez (Isla de Mona)

West

Nicknamed the “Galápagos of the Caribbean,” a remote nature reserve with giant iguanas, sea caves, and towering cliffs.

Reachable only by a ~3–4 hour boat crossing from Mayagüez/Cabo Rojo (DRNA permit required, no street address). DRNA ranger camp at Playa Sardinera; secondary landing at Playa Pájaros.

Laguna Cartagena National Wildlife Refuge

Lajas

West

A freshwater wetland serving as a key stopover for migratory birds.

Entrance off PR-101 via a dirt access road through four gates to an observation tower overlooking the lagoon; refuge office at Carr. 301, Km 5.1, Bo. Corozo, Boquerón. No swimming — freshwater wetland refuge.

Vieques National Wildlife Refuge

Vieques

East

“Protected stretch of beaches, forest, and wetlands,” home to the Mosquito Bay bioluminescent bay.

Main eastern entrance at Carr. 997, Km 3.2, with western entrances at Punta Arenas and Monte Pirata. Named beaches include Playa Caracas (Red Beach) and Playa La Chiva (Blue Beach), plus Puerto Ferro, Playuela, Corcho, and Playa Grande. Multiple named trails, including the Puerto Ferro and Puerto Mosquito trails.

Cabezas de San Juan Nature Reserve

Fajardo

East

Features a 19th-century lighthouse, mangroves, and the Laguna Grande bioluminescent bay; guided tours only.

Visitor center at Carr. 987, Km 5.9, Las Croabas, Fajardo (managed by Para la Naturaleza). Laguna Grande is accessed only via guided kayak tour, not open swimming; the historic Faro Las Cabezas de San Juan lighthouse is now a museum on site.

Humacao Nature Reserve

Humacao

East

Coastal lagoon and mangrove system popular for birdwatching, biking, and kayaking.

Entrance at PR-3, Km 74.3, adjacent to Punta Santiago Beach; on-site trails for walking and biking. The interior lagoon is marked no-swimming.

Punta Tuna Nature Reserve

Maunabo

East

Remote southeast reserve with a lighthouse, coastal cliffs, and sea-turtle nesting beaches.

Entrance/parking at PR-760, Km 0.5, with the “Casa Verde” visitor center at Km 0.9 and the wheelchair-accessible Vereda del Cayur trail. Playa Larga (often called Playa Punta Tuna) is the reserve’s named sea-turtle nesting beach, near the historic Faro de Punta Tuna lighthouse.

Tres Palmas Marine Reserve

Rincón

West

A coral reef system described as a premier snorkeling reserve and winter surf destination.

Shore access via Steps Beach (off PR-413, Km 1.7) — an unmarked residential street with limited roadside parking. It’s the main snorkeling entry point to the reserve’s elkhorn coral, and a winter big-wave surf spot.

Charco Azul

Patillas

South

A mountain watering hole connecting to a waterfall and three-river intersection leading to the Caribbean.

Charco Azul Recreation Area (PR-184, Km 17.8) via PR-52 through Guavate and Carite Forest — a short, easy paved trail (~0.5 mi) leads to the pool.

Survivor Waterfall at Tres Choros

Patillas

South

Three rivers intersecting with a waterfall that leads to the Caribbean.

Survival Waterfall (PR-184, Km 12.3) is reached by crossing the bridge from PR-184 on foot, then turning right to hike the short distance through the woods to the waterfall.