Gahirmatha Beach, Marine sanctuary beach in Kendrapara district, Odisha, India

Gahirmatha Beach lies in Kendrapara district, Odisha, separating the Bhitarkanika Mangroves from the Bay of Bengal. It forms part of the Gahirmatha Marine Wildlife Sanctuary, which covers 1,435 km², of which 1,408 km² is water and 27 km² land including reserve forests, mud flats and accreted sandbars. The nesting beach itself is on the Nasi-I and Nasi-II islands.

The coast received official protection as a marine sanctuary in 1997, after decades of observation showed that an unusually high number of sea turtles lay their eggs here. This decision came in response to earlier losses caused by fishing nets and shore pollution.

The mass nesting is called "Arribada", when thousands of females climb onto the Nasi-I and Nasi-II islands to lay 100 to 180 eggs each in flask-shaped pits about 45 cm deep. Nesting usually happens on dark nights once the southerly wind begins, and the turtles hiss as they lay.

Access is via the town of Chandbali, and visitors should be prepared for sandy paths and warm conditions. Between December and March, nesting observations are possible with permission, while keeping a respectful distance from the animals.

The mass nesting of olive ridley turtles is called "arribada". Females dig flask-shaped pits about 45 cm deep with their flippers and lay 100 to 180 eggs; eggs scooped out by later nesters are called "doomed" because they cannot hatch. Nesting females hiss while laying, when their oxygen intake peaks.