Leatherback turtles nest on the beaches around Cahuita and along the wider Caribbean coast between March and October, with the peak activity running from April through July. The leatherback is the largest of all sea turtles — adults can reach two metres in length and weigh over 900 kg — and watching one emerge from the water, drag herself up the beach, and excavate a nest with her rear flippers is an experience that is genuinely hard to forget. Females return to the beach where they were born to nest, sometimes after decades at sea.
Night tours to observe nesting are organised by local guides working with conservation groups, including ANAI and the MINAE park service. The procedure is carefully managed: groups wait in the dark until a guide confirms a turtle is nesting before approaching, red-filtered torches are used to avoid disorienting the animals, and flash photography is prohibited. Tours typically run from around 8pm and last two to three hours. The combination of conservation value and the sheer drama of the event makes this one of the more worthwhile organised activities on the Caribbean coast. Book through a reputable local guide rather than an independent operator who may not follow protocols.