Coastline attracts people for recreational, residential, entrepreneurial, and industrial activity, resulting in a worldwide phenomenon of coastalization – the shift to the coasts. The proximity to marine coasts is, therefore, a competitive advantage and a development resource for coastal regions around the globe. However, the efficient use of coastal economic-geographical position depends on the numerous external and internal factors, and requires, firstly, a functional delimitation of the coastal zone, and, secondly, an integrated coastal zone management. This article studies the relationship between the proximity to the seacoast and the development of the tourism sector. The aim is to identify the geographical boundaries of using the seaside position in the interest of tourism development; in other words, we identify the functional boundaries of the coastal zone associated with tourist attractions. The research area covers two Russian regions located on the Baltic Sea (Kaliningrad Oblast) and the Sea of Japan (Primorsky Krai). The findings reveal that the optimal zone for developing coastal tourism is within a 10km of the sea, with the most preferable zone extending no further than 1km from the coast. The density of tourist attractions has a positive correlation with the concentration of service sector facilities and infrastructure.