The Data Management Plan (DMP) of the REFLOW project outlines how the project data will be handled during the lifetime of the project and after the project is completed. It gives an overview of which data will be collected, processed and/or generated, which methodology and standards will be applied, whether and how this data is shared and/or made open access, and finally how it is curated and preserved. This initial version of the DMP provides a set of standard guidelines to ensure that all the REFLOW partners manage their data following the FAIR Data principles while being compliant with the EU GDPR. The DMP is a living document and will be updated, whenever significant changes arise, to support the data management lifecycle for all data generated in the project.