Sea Turtle Nesting in Costa Rica

In Costa Rica, 5 species of sea turtles use the black volcanic sand of the country’s coastline to lay their eggs. This is a magic process in which the female sea turtles come onto  the beach to lay eggs after undergoing several hundred kilometers of migrations and enduring the courting of many overly eager males.

First, these females find a suitable spot on the sand. They can be pretty picky, and if something in the environment doesn’t seem right or looks a bit scary, she will go back to the sea without laying the eggs. This is called a false crawl. When a turtle does find the perfect spot and all the conditions are right, she performs a nesting ritual that has been repeated for millions and millions of years since turtles first evolved.

The nesting process starts with the turtle using both front and rear flippers to dig and moving her body around to flatten the sand and remove any debris. This spot is called the “body pit”. Once the body pit is ready, the turtle uses her back flipper to dig a hole in the sand that will serve as the egg chamber. The depth of these chambers varies depending on the species, and larger sea turtles dig deeper egg chambers. Egg chambers are pear-shaped, and the bottom is wider than the hole on the top, and one of the most amazing parts of observing a sea turtle nesting is to watch the precise movements of their rear flippers to scoop the sand out of the egg chamber.

Once the chamber is deep enough, the turtle starts having contractions that will make the eggs come out of their cloaca covered in a mucus that has antibacterial functions. An amazing physiological detail of this process is that the contractions are caused by a peak in the concentration of the hormone oxytocin, which is the same that induces birth in human beings. Unlike humans though, female sea turtles lay about 100 eggs in a nest, and females of most sea turtle species can nest several times in one season. This is a process that costs females a lot of energy, and female sea turtles may take several years to put together enough energy to nest again, whereas males will probably breed every year.

At Turtle Love’s project area, south of Tortuguero National Park, from February through October, four of the five species of Costa Rican sea turtles come ashore to nest and perpetuate the species.

Best Times to See Each Species of Sea Turtles on the Caribbean Coast of Costa Rica

 

Green Turtles Nesting Times (Chelonia mydas)

Green turtles are the second largest sea turtle species and the most abundant on the Caribbean coast. The Turtle Love Project area, on the Caribbean coast of Costa Rica, typically experiences peak nesting activity for green turtles from July to November, with the highest numbers usually seen from July through September. These months are the best time to encounter female turtles laying eggs on the beach. The sight of a green turtle laboriously making her way up the beach to lay her eggs is a profound experience that connects us to ancient natural cycles.

Because nests hatch approximately 60 days after being laid, the best months to see baby green turtles emerging from their nests and making their perilous journey to the sea are September and October. The sight of tiny hatchlings scrambling toward the ocean is both heartwarming and a stark reminder of the challenges faced by this species.

Green turtles also nest in fewer numbers on the Pacific coast of Costa Rica, especially on the beaches of the Santa Rosa National Park. However, the Caribbean coast remains the primary nesting ground for these turtles in Costa Rica.

Leatherback Turtles Nesting Times (Dermochelys coriacea)

Leatherbacks, the largest among all sea turtle species, embark on a remarkable journey to the beaches for egg-laying, creating a mesmerizing spectacle for nighttime visitors. The Turtle Love Project area hosts one of the world’s largest populations of leatherback turtles. These magnificent creatures sometimes travel all the way from the frigid waters of Nova Scotia, Canada, to lay their eggs on the volcanic sands of the Caribbean coast of Costa Rica.

Females come ashore from February through June, with a peak in April and May, which are the best months to witness the nesting process. Observing a leatherback turtle laying her eggs under the cover of darkness is an unforgettable experience, as these gentle giants are incredibly vulnerable during this time. The best months to see baby leatherbacks are May through July, as the hatchlings emerge from their nests and make their way to the ocean, guided by the moonlight.

Leatherbacks also nest in fewer numbers on the Pacific coast of Costa Rica, where the Las Baulas Marine National Park was named after them. Despite the conservation efforts, threats such as fisheries bycatch and illegal harvest of eggs for human consumption have led the population of the eastern Pacific leatherback turtle to plummet in recent decades. The conservation work done on the Caribbean coast is thus critical to the survival of this magnificent species.

Hawksbill Turtles Nesting Times (Eretmochelys imbricata)

Though smaller in size, the critically endangered hawksbill turtles can still be spotted nesting, captivating onlookers with their striking shell patterns—a true delight for the eyes. Adult hawksbill turtles inhabit coral reefs where they eat mostly sponges, which increases the health of the surrounding coral. Their beautiful, patterned shells have historically made them targets for poaching, adding to the threats they face.

Hawksbill turtle nesting at the Turtle Love project area on the Caribbean coast of Costa Rica starts every year in May and lasts until September. These months offer the best opportunity to see female hawksbills coming ashore to lay their eggs. The best time to see baby hawksbills is between June and September, as the hatchlings emerge and begin their journey to the sea.

The conservation of hawksbill turtles is particularly important due to their role in maintaining the health of coral reefs. Witnessing their nesting and hatching is not only a beautiful experience but also a reminder of the delicate balance of marine ecosystems.

Olive Ridley Turtles Nesting Times (Lepidochelys olivacea)

Olive ridley turtles are the most abundant of all sea turtles. Although they do not nest on the Caribbean coast, they nest by the thousands on the Ostional Wildlife Refuge on the Pacific coast. This species is famous for their “Arribadas.” During these events, thousands of turtles come ashore over a few days to nest, creating a truly unique and chaotic natural spectacle.

Arribadas happen year-round and this massive event is synchronized with the crescent quarter of the moon each month. Although Arribadas occur in most months of the year, they vary in intensity, with the most productive Arribadas taking place in October and November. Witnessing an Arribada is an awe-inspiring event, as the sheer number of turtles on the beach creates a scene of bustling activity and life.

Loggerhead Turtles Nesting Times  (Caretta caretta)

Loggerhead turtles, distinguished by their large heads and powerful jaws, emerge onto the shores for nesting at the Turtle Love project area sporadically. While less prevalent compared to other species in Costa Rica, observing their nesting rituals during these months offers a truly unique and memorable experience.

Loggerheads are known for their strong jaws, which they use to crush the shells of their prey, including crabs and mollusks. Their nesting on the Caribbean coast is not as common, but when it does occur, it provides a rare opportunity to see these robust turtles in action. Loggerheads face significant threats from habitat loss and bycatch in fishing gear, making every successful nesting and hatching event critical to their survival.

Conclusion

Costa Rica’s sea turtles offer an unparalleled opportunity to witness one of nature’s most ancient and awe-inspiring rituals. Each species has its unique nesting habits and timing, making every visit to the nesting beaches a new and exciting experience. By understanding the best times to see these turtles and supporting conservation efforts, visitors can help ensure that future generations will also have the chance to marvel at these magnificent marine reptiles.

Whether you’re drawn to the abundant green turtles, the massive leatherbacks, the striking hawksbills, the chaotic arribadas of olive ridleys, or the powerful loggerheads, Costa Rica’s beaches provide a front-row seat to one of nature’s greatest shows. Plan your visit with this guide and prepare to be captivated by the magic of sea turtles in their natural habitat.