The paper is based on the research of the application of the principles of sustainable tourism in protected areas on the example of the Vransko Lake Nature Park. With its beauty of the environment, numerous flora and fauna, it gives a great opportunity to the development of tourism, with which comes a great responsibility because any overexploitation can lead to consequences in the environment. Sustainable development of tourism is based on the dependence of economic sustainability, social responsibility and environmental protection, the successful implementation of which in practice is achieved through the cooperation of the three mentioned, opposing sectors. It is necessary to approach the further development of a certain ecological space with caution and a professional approach so that further spatial pollution does not occur. When looking through the history of the construction of cities and settlements, it can be concluded that in the past much more attention was paid to the culture of construction and materials that were appropriate to the climate than it is today. Thus, sustainable tourism implies the inclusion of the population and coexistence with tourists, while trying to strive that rural households in addition to agricultural activities and offer accommodation and food services, thereby encouraging their place in the tourist supply. In addition, the construction of indigenous accommodation and the provision of indigenous local cuisine is encouraged. The paper is divided into four parts. After the introduction, the first part defines the role and importance of protected areas in Croatia, and briefly explains NATURA 2000. The second part examines the impact of tourism on the environment and studies the concept of sustainable tourism development in protected areas. The third chapter discusses the Vransko Lake Nature Park as a special destination for the development of sustainable tourism due to its natural and cultural values and rich biodiversity, and the way of managing the Vransko Lake Nature Park is presented. The last part of the paper presents initiatives for the sustainable development of tourism in the Vransko Lake Nature Park. The tourism development of the protected area seeks an opportunity for economic development, but knowledge about the specifics and sensitivity of the ecosystem and its biodiversity must not be lost sight of.