Land is a limited resource and represents a strategic asset for tourism development. Tourism transforms land by constructing roads, facilities, and additional amenities to facilitate access and attract tourists. Spatial planning plays a crucial role in this process, particularly in planning land use for tourism in line with strategies for the long-term development of tourism. All tourist destinations rely on effective tourism management to prevent conflicts over land. The emergence of mass tourism in Croatia during the 1960s led to the construction of extensive infrastructure and tourist accommodations to respond to the increasing number of tourists. However, this rapid development often resulted in the degradation of landscape and environment. Building of single residential houses without proper designs and permits, infringement of legal restrictions and master plans have been the main reasons for coastal destruction along the Adriatic. This thesis examines the historical development of illegal and unplanned construction in relation to tourism in the Republic of Croatia. It emphasizes the evolution of spatial planning, tourism carrying capacity, and the significance of spatial plans at all planning levels. Because of widespread presence of illegal buildings, uncontrolled urban sprawl, and the proliferation of secondary apartments, the town of Makarska has been selected for a case study. Although illegal and unplanned construction degraded the landscape and diminished the appeal of Makarska as a tourist destination in pristine nature, the town authorities are now committed to reversing the negative trend. Clear objectives and plans have been set with the aim to achieve the long term sustainable development of tourism, to curb overtourism and to improve the quality of life for local community.