This paper presents the argument that when environmental protection projects favor tourist activities, the travel cost method can be used to measure the value tourists give to the recreational services these areas provide. With this idea we describe a model of tourist behavior that allows us to predict whether a tourist will participate in the reactional activities, the frequency of participation according to the areas' attributes, and the costs of producing alternatives. To illustrate the model's application, we consider tourist demand for and benefits from a set of protected natural areas in Mallorca.