Geo-Seas has implemented an e-infrastructure of 26 marine geological and geophysical data centres, located in 17 European maritime countries. Users are enabled to identify, locate and access pan-European, harmonised and federated marine geological and geophysical datasets and derived data products held by the data centres through a single common data portal. The aims of Geo-Seas are aligned with European directives and recent large-scale framework programmes on global and European scales, such as GEOSS and GMES, EMODNET and INSPIRE. Geo-Seas has expanded the SeaDataNet marine and ocean data management infrastructure to handle marine geological and geophysical data, data products and services, creating a joint infrastructure covering both oceanographic and marine geoscientific data. Common data standards and exchange formats have been agreed and implemented across the data centres. Geo-Seas has adopted and adapted SeaDataNet standards and tools. Geo-Seas also has taken into account the experience and developments arising from international geological projects, such as, OneGeology and GeoSciML. Many of the Geo-Seas partners are also partners in these international projects. Moreover existing international standards are included in the formulation of common standards. The Geo-Seas infrastructure is promoted to research communities, and new data products and services have been developed following consultations on research requirements. Other geological and geophysical organisations are encouraged to adopt the Geo-Seas protocols, standards and tools. The Geo-Seas partnership is assuring the archival and long-term stewardship of data for re-use by new applications in many fields, thus preserving the availability of unique observational data which can be difficult or impossible to re-create.