This document outlines key principles of the Transboundary Diagnostic Analysis/Strategic Action Program (TDA/SAP) approach used for managing international waters. It discusses principles such as adaptive management, ecosystem approaches, sustainable development, poverty reduction, gender mainstreaming, climate change considerations, stakeholder participation, consensus building, transparency, accountability, inter-sectoral policy development, donor partnerships, government commitment, and collaboration. The overall goal of the TDA/SAP process is to facilitate collective management of transboundary water systems and implement reforms and investments to sustainably use ecosystem services.