The Communication, Dissemination, Outreach and Education Plan (hereafter "communication plan") for the Horizon Europe project Blue-Cloud 2026 ("Blue-Cloud 2026") aims to promote and disseminate the project's assets and activities to relevant stakeholders. Blue-Cloud 2026 focuses on developing a collaborative web-based Open Science environment providing simplified access to an unprecedented wealth of multi-disciplinary datasets (from observations or models) as well as access to analytical services and computing facilities essential for ocean science, instrumental for increasing collaboration among researchers, industry, and policymakers. A co-ordinated, efficient and effective 42-month Communication, Dissemination, Outreach and Education Strategy will be implemented, with specific communication and exploitation campaigns for raising awareness of the project, its measurable results, the overall scientific benefits, impacts, and measures for reaching end-users and other stakeholders. The communication campaigns will exploit various communication channels, including the project website, social media, press releases, newsletters, and training & outreach events, amongst others, to engage with its key target audiences, as identified and described in the plan. In particular, the project features the launch of the Blue-Cloud Training Academy, which will focus on building capacity among targeted stakeholders on the use of Blue-Cloud services, and on promoting uptake of FAIR practices in marine research. The plan also highlights the project's active role in discussions with communities engaged in the development of the European Open Science Cloud (EOSC) and digital ocean twinning initiatives, contributing to their potential to drive scientific innovation and economic growth. Through effective communication and engagement with the target audiences, Blue-Cloud 2026 aims to consolidate and expand a community of stakeholders committed to advancing Open Science practices in the marine research domain.