The creation of regional natural parks offers the possibility of improving the economic situation of peripheral regions. However, the use of ecologically sensitive zones for tourism also presents economic, environmental and social problems. The concept of carrying capacity is often presented as a useful approach for determining the intensity of tourism development that can be supported by a region. Our objective thus consisted in the operationalisation of this concept by defining a certain number of indicators to measure different types of carrying capacity. However, the confrontation with the practical realities of the regional natural park Pfyn-Finges in Switzerland made us realise that what we intended to do was more a stylistic exercise than a setup of a management tool adapted to the needs of the park managers. We thus conclude that even though the concept of carrying capacity may have a high heuristic value, its practical value is rather limited.