The Hellenic National Oceanographic Data Centre (HNODC) was established in 1986 from the cooperation of Greece with the Intergovernmental Oceanographic Commission (IOC) of UNESCO. It is part of the International Oceanographic Data and Information Exchange (IODE) network and serves as Greece’s national focal point for acquiring, formatting, quality controlling, cataloguing, archiving, and disseminating marine and oceanographic data and information. HNODC operates within the framework of HCMR and its Institute of Oceanography, the leading Marine Research Organization in Greece and major national data provider for key European data infrastructures such as SeaDataNet, EMODnet, EurOBIS. Since 2021 a new cross-departmental Unit was formed and named ‘Marine Oceanographic Data and Information System” consolidating resources and expertise from HNODC and the Geographical Information Systems Unit. This new Unit facilitates and enhances data management and interacts with all Institutional Departments and Research Infrastructures. Its primary mission is to ensure a FAIR data management approach for the national marine and oceanographic data by adhering to the European and International standards and methodologies. This aligns with the broader goals of the IODE, which seeks to promote the free and open exchange of oceanographic data globally. HNODC’s implementation of FAIR data principles involves several key activities: data discovery, data access, data interoperability and data re-use. HNODC is involved in major European data management projects, infrastructures and networks (such as SeaDataNet-SeaDataCloud, EurofleetsPlus, EMODnet Chemistry, Bathymetry, Blue-Cloud 2026) and is acting as EMODnet Ingestion scientific coordinator.