The objective of MARINERG-i is to become the leading internationally distributed infrastructure in the Marine Renewable Energy (MRE) sector. Its integrated nature and co-ordinated approach will accelerate the research development and deployment of offshore wind, wave, tidal and combined energy technologies and help maintain Europe as a global leader in this industry. In addition MARINERG-i will strengthen European, scientific and engineering excellence and expertise as it’s combined facilities represent an indispensable tool to foster innovation across a large variety of MRE technologies and systems and through all key stages of technology development (TRL’s 1-9). The purpose of this INFRADEV proposal is to undertake development work which will ensure MARINERG-i is effectively positioned to attain the criteria necessary for being successful in a future ESFRI roadmap application. MARINERG-i made an application to the 2016 roadmap and was identified as an emerging RI of EU significance. Since making the bid to the ESFRI 2016 roadmap, the consortium has continued to evolve and collaborate, culminating in the submission of a proposal for a second MaRINET project (MaRINET2) under Horizon 2020 [Infra-IA]. This proposal takes on board the comments and recommendations provided in feedback from the ESFRI 2016 reviewers and has also analysed and updated the positioning of the MARINERG-i concept based on the current status of the sector. In this context it is proposed to: • Broaden the number of member states involved• Create a design study and scientific plan• Develop a business plan including governance, legal, financial and strategic issues • Secure further national support from partners• Create and agree an implementation plan that will bring the proposal to the roadmap.The consortium consists of partners from Ireland, UK, France, Spain, Portugal, Denmark, Sweden, Norway, Netherlands, Germany, Belgium and Italy all of whom will become national nodes.