The protection of natural spaces is a practice that is widely used by governments or nongovernmental organizations seeking to preserve the scenic beauty of landscapes and their natural resources in spaces that stand out for their natural and cultural value and have not been heavily impacted by human activity. Proper tourism management of these spaces can promote the economic, social, and environmental development of a territory and its local communities. The objective of this paper is to examine the role of resources in the performance of protected area tourism destinations from a sustainability perspective. The information provided by the managers of 102 protected spaces in Spain (national parks, nature parks, and biosphere reserves) is analyzed. The results provide relevant information about managing resources to strengthen the sustainable performance of these spaces. The findings indicate that different types of resources affect different dimensions of sustainable performance; for instance, natural resources affect the local quality of life and the area’s sustainability, certain created resources can unite and foster local communities and support environmental sustainability, and some supporting resources can attract tourists.