Marine debris continues to accumulate on coastlines despite repeated clean-up campaigns because we still have a limited understanding of how tides, currents, wind, river discharge, coastal morphology and seasonal conditions transport floating waste. This challenge aims to develop a decision-support platform that predicts where floating marine debris is likely to accumulate before it reaches the shoreline. Rather than reacting after pollution becomes visible, the system will combine oceanographic data, weather information, coastal characteristics and community observations to identify future debris hotspots, estimate arrival timing and recommend priority intervention areas. During the 48-hour Ocean Hackathon, participants will develop a prototype digital platform capable of integrating multiple environmental datasets into an interactive map. The platform may include hotspot prediction, accumulation forecasting, environmental risk visualization, site prioritization, citizen science reporting and clean-up planning tools. The long-term vision is to transform conventional beach clean-ups into science-based coastal management, enabling governments, researchers, NGOs and local communities to deploy resources more efficiently while protecting sensitive marine ecosystems.