NEANIAS is an ambitious project that comprehensively addresses the ‘Prototyping New Innovative Services’ challenge set out in the recent ‘Roadmap for EOSC’ foreseen actions. NEANIAS will drive the co-design, delivery, and integration into EOSC of innovative thematic services, derived from state-of-the-art research assets and practices in three major sectors: underwater research, atmospheric research and space research. Each of these sectors engages a diverse set of research and business groups, practices, and technologies. Each thematic service will not only address its community-specific needs but will also enable the transition of the respective community to the EOSC concept and Open Science principles. In doing so, NEANIAS provides its communities with plentiful resource access, collaboration instruments, and interdisciplinary research mechanisms, which will amplify and broaden each community’s research and knowledge generation activities. From a technological perspective, NEANIAS will deliver a rich set of services that are designed to be flexible and extensible; they will be able to accommodate the needs of communities beyond their original definition and to adapt to neighboring cases, fostering reproducibility and re-usability. From a sustainability perspective, NEANIAS identifies promising, cutting-edge business cases across several user communities and lays out several concrete exploitation opportunities.