Water diplomacy, as one of the effective tools in the management of shared water resources—particularly in regions with transboundary rivers—plays a crucial role in reducing tensions and strengthening regional cooperation. This study, employing an applied approach and a descriptive–analytical method, provides a geopolitical analysis of water diplomacy in Iran’s border rivers. To better conceptualize the issue, three converging theoretical frameworks in international relations—neoliberal institutionalism, liberalism, and constructivism—are utilized. Accordingly, the main research question explores how these theoretical approaches can contribute to an effective analysis of water diplomacy in Iran’s transboundary river basins. The central hypothesis posits that an integrative application of these theories can lead to a more accurate understanding of geopolitical relations, reduction of regional tensions, and enhancement of cooperation mechanisms between Iran and neighboring countries in managing shared water resources. The findings—drawn from the application of these approaches to three case studies (Helmand, Harirud, and Aras rivers)—indicate that despite their theoretical differences, all three frameworks emphasize institutional capacity building, economic interdependence, and the formation of shared identities and norms. These elements, in turn, can provide a solid foundation for enhancing water diplomacy across Iran’s borders. The study also highlights that adopting a synthesized approach can significantly assist policymakers in formulating comprehensive and multi-dimensional strategies for the sustainable management of transboundary water resources.
