Laguna de Manialtepec

Laguna de Manialtepec is a coastal lagoon about 15 km long, lying 16 to 18 km west of Puerto Escondido along Highway 200 toward Pinotepa Nacional. Most of the water lies in the municipality of San Pedro Mixtepec, while the western shore, including the village and docks of San José Manialtepec, belongs to Villa de Tututepec. The name comes from Nahuatl and is usually translated as "water born from the hill", after a warm spring that feeds the lagoon. A sandbar separates it from the Pacific; during the rains, roughly July to September, the lagoon breaks through to the sea at a spot called Puerto Suelo or El Carnero.

The water is a mix of fresh, salt and spring water, often tinted reddish by the mangroves and red algae. Red and white mangroves line the shores, some up to 15 m tall, with patches of forest between them. The lagoon is one of the best birding spots on the Oaxaca coast: herons and egrets of many kinds, brown pelicans, wood storks, white ibis, ospreys, kingfishers, frigatebirds and parrots are all seen here, and migrants from as far as Canada spend the winter. Green and black iguanas sun themselves in the trees. Fishing for mojarra and snook and small-scale ecotourism are the main livelihoods around the shore.

Visitors explore the lagoon by boat or kayak. Local boatmen run trips of around an hour and a half through the mangrove channels and out to the sandbar, where the lagoon, the Manialtepec river and the sea meet. At night the lagoon is known for bioluminescence: microscopic plankton that glow blue when the water moves, so every paddle stroke, fish and trailing hand leaves a streak of light. The glow is strongest in the rainy season, roughly May to November, and best on dark, moonless nights; it varies from night to night and is never guaranteed.