The economic valuation of goods that do not have a market, like services offered by natural parks, provide a lot of information for the purpose of policy making on the conservation and protection of the natural environment, as well as for establishing park use strategies for potential park visitors. In this respect, this paper aims to analyse visitor preferences for Cornalvo Natural Park, which has been classed, since 1992, as a Site of Community Importance. To do this, we conducted an analysis adopting the choice experiment methodology to determine visitor preferences for a set of attributes. Additionally, we included a visitor preference heterogeneity analysis based on a mixed logit model in order to calculate individual willingness to pay with respect to a set of previously specified attributes. Finally, we also implemented the latent class methodology to define groups of individuals with similar characteristics. The information was gathered from visitor surveys conducted during 2019. The main results show that tourists had a high preference and willingness to pay for higher biodiversity levels and lower numbers of visitors, whereas the other attributes were less relevant. Additionally, we detected some degree of heterogeneity in willingness to pay by sex, age and income. Finally, Latent class analysis identified two visitor classes, determined primarily by age and income.