In choosing to explore the southern coast of Chiapas from Tonalá to Tapachula, you are taking a resolute step off the beaten path of touristy Mexico. Its beaches with grey and black volcanic sand, and its rough waves and currents have protected it from mass tourist development. Long strips of sand (barras) separate the Pacific Ocean from the lagoons, "dead" seas lined with mangrove swamps where many birds take refuge. The foothills of the Sierra Madre de Chiapas are only about ten kilometres away.