Huatulco's undeveloped areas are to the west of Santa Cruz, its beaches are less developed; in fact most of this area still belongs to the Parque Nacional Huatulco.

This is a protected area "Área Natural Protegida" created in 1998. It contains 6,375 hectares of lowland jungle and 5,516 hectares of marine areas, encompassing the bays of Bahía Maguey, Bahía Órgano, Bahía Cacaluta, Bahía Chachacual and Bahía San Agustín. In these bays live the most important coral communities of the Mexican Pacific.

Approximately, 723 species of animals live in the park as well as a number of species of colorful fish, and it is open to scuba diving, bird-watching and hiking. In 2006, the park received certification from Green Globe, mostly due to it management of potable and waste water, the first resort in the Americas to do so, and the third in the world.

Bahía Órgano is named for the cacti that grow there. It is 240 meters long and only accesible by boat. Bahía Maguey is about 1/2 km long and is accesible by car. Both these bays have fine, white sand and waters of various colors of blue and green. Bahía Cacaluta and Bahía Chachacual are only accesible by boat, but there there are absolutely no human constructions of any kind. Bahía San Agustín is the furthest west and the largest of all the bays. It has 1 km of beaches between 20 and 80 meters wide. There are also small islets inside the bay itself.