Energy islands are seen as energy hubs which have potential to support the production and storage of renewable energy, including green hydrogen, and ammonia. The focus of this study is on the energy islands connected to offshore wind farms and offshore green hydrogen production with the aim to investigate different aspects linked to energy islands acting as strategic infrastructures for the development of green corridors. Identification and analysis of challenges faced by the energy island and green corridors are part of this research approach. Insights are drawn from the analysis of academical studies and industrial projects, and blended with the findings from a wide array of stakeholders. The challenges related to the critical raw materials and their supply chain exhibit important role in the green maritime road map and recommended policies due to the fact that development of offshore wind farms and green hydrogen can be critical materials intensive.