San Dionisio del Mar is a town and municipality in Oaxaca in south-western Mexico.

[1] The municipality covers an area of 237.3 km2 at an elevation of 10 meters above sea level and includes a peninsula in the Gulf of Tehuantepec on the Pacific coast.

Wild fauna include iguana, armadillo, opossum, pigeon and rook.

[1] The municipality is home to the Huave people, who speak a unique language unrelated to any other.

The people also practice agriculture, growing maize, sesame, sorghum, squash and fruit, and keep cattle, horses and pigs.