The European marine projects and landmarks jointly present a significant asset to support the observation, monitoring, and study of marine systems from the land to the open ocean. Together, with the marine RI projects, they can provide an integrated pan-European multidisciplinary platform, combining in situ and remote observations of physical, chemical, and biological parameters with experimental manipulation, to provide the basis for a holistic understanding of European marine systems and support European policies. Collaboration between environmental RIs is necessary to effectively support the progress towards implementing the European Ocean Observing System (EOOS) and efficiently using the available infrastructure, human and financial resources. JERICO, in collaboration with other environmental RIs, has taken steps to foster the collaboration, and to effectively support the progress towards implementation of the EOOS.