The objective of this study was to analyze the potential of the Gurupi-Piriá Marine Extractive Reserve, Federal Conservation Unit, located in the municipality of Viseu, northeast coast of Pará, pointing sustainability indicators appropriate to the local reality. This work seeks to fill the gap of information about the notions of the Gurupi-Piriá RESEX beneficiaries about the tourist activity, as well as the collection of data that can guide the implementation of activities of public use, in order that this use can happen minimizing possible conflicts and looking for socio-cultural sustainability. It was developed according to the principles of quantitative-qualitative research that allowed the participation of the actors of the communities involved. The prospecting tool used was the application of questionnaires to two hundred beneficiaries of Resex Gurupi-Piriá. The results showed both the empathy, expectations and fears of the participants in relation to tourism, as well as the need for their qualification to perform the role that is right for them in the initiatives to be implemented in this area. Community Based Tourism, according to the author, has shown itself to be the branch of tourism that is more in line with the principles of sustainability in tourism in protected areas with traditional populations. At the end, a set of ten easy-to-apply indicators for periodic assessment of the sustainability of tourism activity in Resex communities was suggested. Keywords: Marine Extractive Reserve of Gurupi-Piriá, Sustainable Tourism, Tourism in Protected Areas.