Tourism has become one of the most dynamic sectors of modern economies, contributing significantly to regional development. However,

the rapid growth of tourist flows has led to the emergence of overtourism, which negatively affects local communities, natural environments, and the quality of tourist experiences. This paper examines legal and administrative instruments used to manage tourist

flows in the context of sustainable regional development. Particular attention is paid to the relationship between environmental law and tourism management, including the concept of “use exceeding common use” under environmental law. The study also analyses practical governance tools such as zoning, pricing policies, capacity limits, and stakeholder involvement. Using examples from Lithuania and Poland, the paper demonstrates that effective management of overtourism requires an integrated approach combining legal regulation, administrative measures, and innovative management strategies.