This study traces the development of the international law related to the free access of landlocked States to and from the sea. Part I is a brief introduction to economic, institutional, and development-related challenges faced by landlocked States. Part II examines doctrines and theories that have influenced the evolution of the legal regime that applies to landlocked States. Part III reviews the progress the international community has achieved over the decades in devising legal mechanisms to address the problems these States face. It discusses enforcement of the right of access, in particular, the administrative, institutional, and technical mechanisms used. The study further analyzes bilateral treaties and agreements dealing with the question of transit in different continents. These agreements aimed at facilitating transit between landlocked States and their transit neighbors provide for regimes that are tailored to the specific geopolitical and socioeconomic needs of the parties. The study also discusses the different international resolutions bearing on cooperation between landlocked States and the role of multilateral institutions. Finally, Part IV concludes the study by highlighting positive achievements of the international community in working toward a regime that is satisfactory to all, and describes a multifaceted approach to solve the problems of access of landlocked States.