The overarching goal of ENVRI-FAIR is that all participating research infrastructures (RIs) improve their FAIRness and become ready for connection of their data repositories and services to the European Open Science Cloud (EOSC). Deliverable 9.1 has reported on the roadmap of the RIs in the marine subdomain towards improving their FAIRness. It presented the approach of using FAIR questionnaires (together with WP5) to identify the strengths and weaknesses of each RI and a first indicative set of activities foreseen to improve identified weaknesses or gaps. After formulation in Deliverable D9.2 of implementation plans for mitigating these gaps during the next phase of the ENVRI-FAIR project, the RIs from the marine subdomain have specified in Deliverable D9.3 the technical services and interfaces to be implemented at RI level and have undertaken the implementation. The RI services are demonstrated in this deliverable D9.4 (M27) and will be operational for EOSC operations in D9.5 (M36).