Understanding complex and transboundary aquifer systems and groundwater-surface-water interactions is indispensable for effective integrated water management, particularly under the stress associated with groundwater depletion, quality deterioration and the regional effects observed under climate change. Under the new four-year IAEA Technical Cooperation project RER7013, 38 institutions from 27 countries in Europe and the Central Asia region grouped together into 7 case studies with different geographic and thematic focuses to enhance cooperation in the field of water and isotope hydrology in the region, support the development of new technical capacities and competencies, as well as help clarify persisting issues in the region related to the sustainable management of transboundary water resources. These case studies cover several regional and transboundary problems, including the impact of climate change on karst aquifers and groundwater/surface water interactions in the Western Balkans, groundwater nitrate contamination in Eastern Europe and Caucasus, the vulnerability of stratified transboundary aquifers to over-abstraction and pollution, as well as contamination problems of selected costal aquifers in Europe. Other topics include water balance and quality control in Central Asia, and the influence of climate change on the water resources used for irrigation in the SW East-European plain. In this project, isotope hydrology laboratories in the Europe and Central Asia region with different levels of capacity are thus cooperating and working on solutions to a common, often transboundary, water resources management related questions. This collaboration provides a favorable opportunity and unprecedented insights to jointly analyse the status of existing technical capacities and competencies in isotope hydrology in the participating countries: How many isotopes enabled research groups are active and working on transboundary questions? Are research groups in the region equipped on a state-of-the-art level? Are scientific capacities sufficiently developed to cover the demand in the region and to provide answers to relevant water management questions raised by water authorities and policy makers? Naturally, the answer to these questions is of high importance to efficiently manage the development of national and regional capacities, both from the viewpoints of the individual Member States and from the view of regional actors in technical collaboration, such as the IAEA. Furthermore, the use of isotope methods in the region will be strengthened by investigating collective measures for quality control of isotope analyses and results, and by exploring efforts to harmonize the technical approaches of the different participating laboratories.