This document discusses regional cooperation on water and climate adaptation. It notes that climate impacts cross borders and force migration. Adaptation efforts should also cross borders. It aims to support regional economic communities, river basin organizations, and governments to advance regional cooperation on climate adaptation for transboundary waters and shared aquifers. Specific objectives include defining regional investment options to enhance water security and resilience, enhancing collaboration on adaptation measures, and supporting regional integration and use of climate information. Key outputs will be support packages to develop agreements, commitments, and tools integrating water security and climate resilience. Examples of activities include regional assessments, analyzing hydroclimate data, and supporting investment decision making.