The Tools4Ocean project will develop a comprehensive, innovative framework to address marine plastic pollution for the Arctic/Atlantic regions through an integrated Digital Toolbox leveraging advanced technologies, citizen science, and stakeholder engagement. The development of the Toolbox will follow a co-design approach involving a wide network of public authorities, NGOs, industry actors, and citizen scientists, ensuring solutions are socially accepted, environmentally sound, and practically applicable. Building on existing high-TRL solutions, the project will advance the state of the art by deploying scalable, cost-effective monitoring systems with focus on citizen science. The toolbox will support open data, decision-support systems, and modular, interoperable components compatible with EU systems like EMODnet and the Digital Twin Ocean, ensuring long-term sustainability. The project also emphasizes source attribution, transport pathway analysis, and hotspot identification, crucial for designing effective reduction measures. Effective prevention measures include community engagement, incentives like bans and levies to reduce plastic use. For removal and intervention, innovative technologies including barriers and settlement ponds are deployed to intercept plastics before reaching the ocean. Combining these approaches significantly decreases plastic influx in marine environments, supporting sustainable management and policy goals. To demonstrate practical effectiveness, Tools4Ocean will implement and evaluate at least three use cases in diverse geographical and socioecological contexts, including Arctic sites in Svalbard and Troms, and Atlantic sites in Plymouth, UK, and Porto, Portugal. These real world use cases at test sites will facilitate co-design with local stakeholders, validating innovative monitoring technologies. In addition, the implementation will be replicated at three associated regions to further evaluate the practical usage of the Toolbox.