The Baltic Sea Region There are different approaches to the definition of the Baltic region. They depend on the objectives of the study. We will consider the Baltic region as the territory of countries with access to the Baltic Sea. Sustainable Tourism There are different approaches toward the definition of the term "sustainable tourism." The most commonly used is close to the general definition of the sustainable development but applying not to all the population, but just to visitors who must respect and preserve the environment in the destination for future travelers. However, 1 day each of us becomes "a visitor." Another approach defining it stresses the triangular essence of the term, based on economic, social, and environmental impacts, arising during travel "addressing the needs of visitors, the industry, the environment and host communities" (Making Tourism More Sustainable: A Guide for Policy Makers 2005). So, it is possible to underline that there are two sides of the sustainability as far as tourism is concerned: internal sustainability, connected to tourist himself (his/her feeling, behavior, attitude, etc.) and external (connected to the socioeconomic, political consequence of travel). Transborder or Transboundary Tourist-Recreational Region It could be considered as the compactly located territories of neighboring regions of neighboring countries that have a common tourist resource that ensures the functioning of territorial combinations of economic entities united by substantial ties (Kropinova 2016, 2020a).