Drift to sleep pondering the waves crashing onto the black-sand beach at Madre Sal, an ecotourism project 25km south of Puerto Arista. Named for a mangrove species, its restaurant (meals M$120 to M$150) and 18 thatched two-bed en suite cabañas sit astride a skinny bar of pristine land between a lagoon and the Pacific that’s reached via lancha (motorboat; M$25) through mangroves.
Crabs skitter along the sand when stars fill the night sky. In season, sea turtles come ashore to lay eggs, and the night watchman can wake you if you want to watch or help collect the eggs for the Boca del Cielo hatchery.
Though the water can be rough, the beach is spotless, and there’s excellent bird-watching in the mangroves (think 250 species of birds in the area), including 13 species of heron. Two- to three-hour lancha trips are available (M$800 per boat, maximum 12 people), including one for bird- and crocodile-spotting (M$1200 per boat).
From Tonalá, take a taxi (M$50 shared, M$500 private) or combi (M$40) to the embarcadero (boat launch) at Manuel Ávila Camacho; or from the village you can walk five minutes or ride on the back of a motorbike (M$10).