This document summarizes the DIKTAS project, which aims to facilitate sustainable use and protection of the Dinaric Karst Aquifer System, a large transboundary aquifer in the Balkan region. The project seeks to improve understanding of the resource and its environmental status, establish cooperation among countries, and harmonize policies. Initial achievements include establishing a project structure and completing analyses and stakeholder participation. The overall goals are equitable and sustainable use of water resources while protecting unique groundwater ecosystems.