The Special Nature Reserve “Kraljevac” (RK) is located in the Autonomous Province of Vojvodina, in southern Banat. This first-category reserve covers an area of 264.3 ha and represents a natural item of exceptional importance. The reserve is characterized by significant geological heritage such as loess sections and dune relief, a lake with famous floating peat islands that form the physiology of this wetland, and very rare representatives of flora and fauna. The RK is characterized by the rich cultural heritage of the population living in South Banat. The different ethnic composition of the population and multiculturalism are the main sociocultural tourist motives of this protected area. The Deliblato Sands, known in Europe for their rare geological features, flora and fauna, are located in the immediate vicinity. This significantly increases the value of the RK. Quantitative methodology was used in the paper, which included interviewing respondents as a research technique. The research was conceived according to the Prism of Sustainability (PoS) model. For this sustainable tourism research, a total of 750 respondents (470 residents and 280 visitors) were surveyed. A written and online questionnaire was used in the survey of respondents. By using a questionnaire, respondents expressed their views on certain statements that were grouped into two categories. The claims refer to the natural and sociocultural factors of tourism development in this protected area. Both categories of tourism destination factors can significantly influence sustainable tourism. In addition, we examined the impact of sociocultural and natural factors on respondents’ satisfaction with sustainable tourism. The research results indicate that there is a significant influence of these factors on the satisfaction of residents and visitors with sustainable tourism. The results of this research can provide important information when planning the development of tourism in this protected area. Also, the results can help in the evolution of tourism development at the local, national and regional levels. The forms of tourism that could be central in the RK are scientific research, sports–recreational, ecotourism, bird-watching, events, cultural, gastronomic, and other tourism forms. These forms of tourism can provide environmental, economic and social benefits for this protected area as a tourism destination.