Adventure tourism, as an alternative form of tourism, should follow the principles of sustainability. This study was conducted in Três Coroas, an adventure tourism destination characterized mainly by whitewater rafting. The aim of this work was to evaluate the sustainability of adventure tourism activities in Três Coroas using the Adventure Tourism Development Index (ATDI) criteria. A descriptive approach was used, with qualitative and quantitative aspects. Survey data were collected through interviews, participant observation, and a literature search. These data were used to evaluate and classify adventure tourism in the municipality according to the ATDI criteria. The relationship between the public authority and entrepreneurs was evaluated as positive in that they consider tourism as a strategic factor for the city’s development, and the quality of services and infrastructure. Negative aspects identified were a lack of control in relation to carrying capacity of the environment, problems of pollution of the Paranha River, and a lack of basic services for the population. The implementation of innovative activities, and the attraction of smaller niches, could add value to the tourism product without having to increase the demand and infrastructure.