Las Baulas National Marine Park protects 445 hectares of Pacific coastline and mangrove estuary where leatherback turtles nest between October and March. Established in 1991 to safeguard nesting sites at Playa Grande, the park anchors a 22,000-hectare conservation corridor stretching from Tamarindo Bay north to Cabo Velas. The mangrove channels that feed into the estuary support spotted eagle rays, white-tipped reef sharks, and seasonal pods of bottlenose dolphins. Morning departures from Tamarindo Marina traverse open water where frigatebirds and brown pelicans dive for sardine schools pushed shallow by the incoming tide. Tamarindo boat tours operate year-round from the municipal marina, with catamaran operators holding permits to navigate both the marine park boundary and the unprotected waters of Flamingo Bay to the north. The volcanic headlands that frame the bay drop to reef systems at depths of six to twelve meters, frequented by parrotfish, angelfish, and green sea turtles grazing on algae beds. Snorkel sites rotate based on visibility and current strength; calmer conditions typically prevail between December and April, when Pacific swells diminish and water clarity improves to fifteen meters. Sunset cruises depart at 15:30 during dry season and 16:00 in the green months, timing the return to coincide with the six o'clock descent behind the Nicoya Peninsula ridgeline. Operators ranging from twelve-passenger sailing vessels to forty-seat catamarans run daily schedules, with onboard naturalist guides required under park regulations for any vessel entering protected waters. The conservation fee collected at park entry funds leatherback monitoring programs and mangrove restoration along the Matapalo River, which connects inland wetlands to the coastal nursery zones. Multi-hour itineraries blend open-ocean sailing with anchored snorkel sessions, typically including a midday meal prepared onboard. Night tours focus on turtle observation along Playa Grande, restricted to guided walks with red-filtered headlamps to avoid disrupting nesting behavior. The marine park designation imposes vessel speed limits within one nautical mile of shore and prohibits anchoring on live coral, standards enforced by SINAC rangers stationed at the Playa Grande office. Regional operators coordinate departure times to prevent crowding at snorkel sites, with morning slots reserved for photography-focused trips and afternoon departures catering to the sunset cruise market. Water temperature holds steady at 26–29°C throughout the year, eliminating the need for wetsuits outside of extended dive sessions.