An archeological site in Huatulco is the Bocana del Río Copalita archeological site and museum, five miles from the city. The earliest remains of this pre-Hispanic site date back 2,500 years and lay at the boundary between the Mixtec and Zapotec areas.

The site, known simply as Copalita, has been excavated since 1988 by Mexico’s Institute of Anthropology and History (INAH). Visitors can access the building complex where the ruling class would have lived in the first six centuries B.C.: Templo Mayor or structure four; structure two or Temple of the Serpent; terrace one and the Ball Court, with its stones engraved in low relief. The entire site comprises 86 acres waiting to be explored.

Coastal navigation was controlled from this site — the only one yet found with a navigation aid, which consists of a stela located on the top of the cliff to help guide the cayuco canoes out at sea.

It was also strategically located on the river banks and near the sea.This let them exploit fresh water and salt water resources, their main activities being fishing and gathering products for their own consumption and to exchange with other peoples.