Mura, Drava and Danube (MDD) form the lifeline of one of the most valuable river corridors in the Danube Basin. However, connectivity within the corridor is reduced due to human-made changes to rivers and their natural processes. While DTP-project coopMDD established a living cooperation between Protected Area managers and a Transboundary Management Programme for the planned 5-country Biosphere Reserve MDD, the knowledge base and transboundary cross-sectoral cooperation stays insufficient. This leads to unused opportunities for synergies between multiple aims in river management. lifelineMDD addresses these issues with a cross-sectoral partnership, aiming to improve connectivity and biodiversity within the MDD river corridor by restoration of natural river dynamics. The development of a strategic integrated approach to river restoration in the transboundary bio-corridor will be based on scientific studies of bio-indicators fish and river birds and abiotic framework conditions sediment transport and climate change. A cross-sectoral learning process between nature protection and water management authorities based on pilot restoration actions will raise institutional competences and cooperation between key stakeholders. Involvement of NGOs, local and national policy levels will ensure sustainability of results by awareness raising in the local population and development of lasting stakeholder platforms. By providing an integrated transboundary strategic framework for river restoration based on research, pilot restoration and joint learning, lifelineMDD will strongly contribute to the DTP objective of protecting and restoring ecological corridors and raise cooperation between main actors. The project contributes to close connectivity gaps defined in the EUSDR study “Ecological Connectivity in the Danube Region”, e.g. research gaps on complex ecological processes, cooperation gap between nature protection and other sectors, geographic gap on tributary rivers.