Blue-Cloud 2026 builds upon the pilot Blue-Cloud project which established a pilot cyber platform, providing researchers access to multidisciplinary datasets from observations, analytical services, and computing facilities essential for blue science. Core services delivered are the federated Data Discovery & Access Service (DD&AS), the Virtual Research Environment (VRE) and Virtual Labs. Blue-Cloud 2026 aims at a further evolution of its pilot ecosystem into a Federated European Ecosystem to deliver FAIR & Open data, analytical services, instrumental for deepening research of oceans, EU seas, coastal & inland waters. It develops a thematic marine extension to EOSC for open web-based science, & serves needs of the EU Blue Economy, Marine Environment and Marine Knowledge agendas. Blue-Cloud 2026 in 42 months covers activities at a growing number of federated environmental RIs to improve & optimise services for uptake of new data sets from a multitude of data originators and for discovery and access to their structured data collections. The advanced ecosystem will provide a core data service for the Digital Twin of the Ocean, mobilising and making available major additional data resources as validated and harmonised in-situ data by means of Data Lakes. The modular architecture of the VRE is scalable & sustainable, fit for connecting additional e-infrastructures, integrating more blue analytical services, configuring more Virtual Labs, and targeting broader (groups of) users. Blue-Cloud 2026 main KERs: A) FAIR compliant DD&AS; B) Open Science VRE federating multiple e-Infrastructures; C) 3 EOV WorkBenches; D) 5 Virtual Labs; E) Blue Strategic Roadmap; F) DTO Task Force. Blue-Cloud 2026 is co-ordinated by the same organisations Trust-IT & MARIS, counting on the same core team of partners CNR, Ifremer, MOI, Seascape Belgium, VLIZ; overall it mobilises a solid, multidisciplinary, & committed team of 40 partners from 13 EU countries.