The principle of public participation is reflected in several rules of international law. This article will highlight the role of individuals and communities in three branches of international law, i.e. international water law, international environmental law and human rights law. Each of these typologies of norms gives specific features to the principle of public participation in transboundary water resources management. International water law stresses that the transmission of information on water quality should be part of regimes on international watercourses. International environmental law, putting emphasis on public participation during the environmental impact assessment (EIA) process, indicates that a prevention approach should be adopted in order to prevent damage to international watercourses. Finally, international human rights law consecrates public interest issues on the management of water resources and entitles individuals and communities to receive information and to be consulted in the management of water resources.