What happened to the leatherback turtle tours in Playa Grande?

For decades, Playa Grande was recognized as the most important nesting site in the Eastern Tropical Pacific for the leatherback sea turtle (Dermochelys coriacea). During the 1988–1989 season, scientific estimates indicated that around 1,500 females laid their eggs on the park's beaches. On any given night, it was common to see dozens of leatherbacks nesting simultaneously along the shoreline.

Unfortunately, the population has suffered a precipitous decline of over 95% since the late 1980s. In recent seasons, the number of females recorded during the six-month nesting season (October to March) has dropped to critically low levels, with only 2 to 8 individuals counted per season across the entire park. Due to the extreme difficulty in spotting turtles and to prioritize the species' well-being, the Matapalo Local Guides Association permanently suspended nighttime turtle-watching tours in 2019.

Why did the leatherback turtle population decline in Playa Grande?

Scientists from The Leatherback Trust's monitoring project have been studying the leatherback turtle population since the early 1990s. They report that the population collapse stems from a combination of historical pressures and ongoing threats both at sea and on land:

1. Historical egg poaching: Between 1970 and 1990—prior to and during the creation of the national park in 1991—nearly 90% of the eggs laid on the beaches were systematically harvested. Because leatherback turtles take decades to reach sexual maturity, the severe consequences of this massive egg removal became evident years later as recruitment rates dropped.

2. Bycatch on the high seas: Incidental capture by longline and gillnet fisheries in international waters and feeding grounds in the South Pacific (particularly off the coasts of Chile and Peru) remains a primary driver of adult mortality.

3. Development and pressure in the buffer zone: Coastal infrastructure surrounding Playa Grande has expanded more than tenfold since the park's establishment in 1991, growing from 47 structures to 487 in 2024. Real estate expansion in the buffer zone and encroachment into protected areas place heavy strain on critical nesting habitat.

4. Light pollution and disorientation: Increased artificial lighting from beachfront developments and nearby towns disorients both nesting females and hatchlings, impairing successful egg laying and preventing hatchlings from reaching the ocean.

5. Predation by domestic animals and opportunistic wildlife: Inadequate waste management linked to urban growth has led to a population surge in opportunistic species such as raccoons (Procyon lotor). Combined with uncontrolled access by dogs and other pets, nest predation rates have reached alarming levels of 84% to 100%.

6. Climate change and incubation temperatures: Rising coastal temperatures driven by climate change alter ambient humidity and internal nest temperatures, skewing hatchling sex ratios and severely compromising hatching success.

7. Vulnerability of coastal aquifers: The coastal strip and the Huacas-Tamarindo aquifer face severe water vulnerability and saltwater intrusion risks due to overexploitation, threatening the freshwater resources essential to local ecosystems and protected area management.

Crecimiento urbano en la zona de amortiguamiento del Sector Playa Grande en el Parque Nacional Marino Las Baulas de Guanacaste entre 2003 (columna de la izquierda) y 2026 (columna de la derecha) en (a) Playa Grande Norte y (b) Playa Grande Sur. En la zona central de Playa Grande aún no hay edificaciones, aunque existen planes para su desarrollo.
Fuente: Cordero-Umaña y Santidrián Tomillo, Ambientico, 2026

From observers to guardians: participatory science and environmental education

In response to these challenges, conservation efforts at Playa Grande have shifted focus. Rather than promoting high-volume wildlife tourism, local organizations and researchers have joined forces to protect every nest and actively engage the local community:Continuous research and monitoring: For over 30 years, scientific teams from The Leatherback Trust and international researchers have conducted population monitoring throughout each nesting season.

• Off-season monitoring: From April to September, the Specific Development Association for the Conservation of Playa Grande (ADEC)—in partnership with SosGrande, The Leatherback Trust, and SINAC—carries out regular beach patrols and surveillance with community support.

• Surveillance on secondary nesting beaches: We collaborate with KUEMAR and SINAC to monitor and record nesting events across the beaches of the Baulas Conchal Coastal Marine Biological Corridor.

• Classroom and community education: In partnership with McGill University, Villarreal High School, and Playa Grande School, SosGrande helps implement a marine conservation curriculum. Through interactive readings of the children's book about Aura the sea turtle and "Discover the Leatherback Sea Turtles" workshops, we bring marine science to students, youth, and visitors.

Where is Aura?

Tatiana and Tin Tín, the mangrove hummingbird, venture out with several friends in search of Aura, a leatherback turtle who has not returned to Playa Grande.

How you can support conservation efforts

The National System of Conservation Areas (SINAC) reminds residents and visitors that the park's nesting beaches have restricted nighttime access. Activities such as camping, building fires, and bringing pets are strictly prohibited to safeguard endangered wildlife.

When visiting Playa Grande or surrounding areas, you can help by taking these actions:

• Participate in community activities: Join SosGrande's ecological expeditions and educational workshops to learn about marine biodiversity and support local environmental education.

• Respect beach regulations:

  • Avoid using white lights, flashlights, or flash photography on the beach at night.

  • Keep pets off nesting beaches to prevent predation on eggs and hatchlings.

  • If you encounter nesting turtles or hatchlings, remain at least 5 meters (16 feet) away and maintain a clear path to the ocean.

  • Note that Grande, Ventanas, Carbón, and Langosta beaches are closed daily from 6:00 PM to 5:00 AM.

• Report sightings or violations:

  • Report incidents directly to Las Baulas National Marine Park authorities at +506 8704-6444.

  • Contact the SosGrande community ranger committee at +506 8378-9640 for local assistance.

Purposeful Tourism: Ways to Collaborate with SosGrande

Ecotourism offers a regenerative travel model that converts travel experiences into direct action for conservation, education, and community development. By participating, visitors directly support research, monitoring, and habitat protection.

• Sea turtle hatchling expeditions (January to March): Work alongside researchers to assist with nest evaluations and the safe release of hatchlings into the ocean.

• Tamarindo Wetland monitoring: Take a guided boat survey along coastal estuaries to monitor bird populations and record American crocodile activity.

• Tropical Dry Forest restoration: Join guided nature walks and assist with hands-on habitat restoration projects in private reserves.

• Drone technology for marine conservation: Participate in hands-on workshops demonstrating how aerial drones are used for wildlife monitoring and threat assessments.

• Marine debris workshops: Engage in citizen science by sampling debris along Playa Grande and helping categorize marine plastics for analysis.

• Conservation volunteer days: Support local efforts through beach cleanups, firebreak maintenance, and environmental education activities at area schools.