SEAMLESS participates in the Open Research Data Pilot (ORDP) and follows the FAIR (Findable, Accessible, Interoperable, Re-usable) data paradigm and this is reflected in this Final Data Management Plan (DMP). This DMP details the management of data generated within the SEAMLESS project. It covers: • what has been generated, • how data have been handled during and will be after the project, • who owns a data set and with whom it is shared, • how sharing of data within and outside the project is organised, • what formats, metadata and standards the data have adhered to. The SEAMLESS data sets consist of numerical simulation outputs generated by a range of marine ecosystem models and data assimilation systems. The code of the models and data assimilation systems themselves were a major outcome disseminated by the project. This DMP describes relevant procedures put in place during the project to adhere to principles of accessibility and interoperability, ensuring that both the data and codes developed by the project are useful to project partners and to other stakeholders.