Sustainable tourism, carried out on spa tourism enterprises, is a key issue that requires the combination of the implementation of economic goals of business activity and, at the same time, the limitation of negative influences on the tourist areas, which are valuable from the point of nature. The main objective of this article and, at the same time, the objective of theoretical–cognitive and empirical research, is to find links and mutual relations between the entities carrying out tourist and therapeutic activity in health resorts in a model approach, taking into account sustainable tourism elements. The implementation of the goal will be carried out on the basis of empirical studies, covering business models of 17 of the largest health resorts in Poland. The article describes relations occurring in the health resort environment and defines a model of relations between health resort enterprises and other entities functioning within this sector. The network approach of the studied issue is analyzed from the point of view of relations found in the complementary cooperation of entities, among which one is ready to implement the benefit and others express their need for the said benefit and are willing to be its recipients. The network relation of the second type, where the entities combine their forces to meet a common goal, is presented in the form of exemplification of the health resort enterprise network in the Polish market.