Southeast Asia’s extensive coastline contains a suite of blue carbon ecosystems that all play important roles in the storage of carbon – a so-called Nature Based Solution for climate mitigation. However, the scale of this stored carbon, and how it may respond to future climate change is uncertain, and remains a key hinderance in the widescale adoption of blue carbon conservation policy. In the SCOPE project, we are mapping the carbon storage potential of key blue carbon ecosystems along the Vietnam and Cambodia coastline: mangrove forest, seagrass meadows, coral reef lagoons, tidal marshes and mud flats. Our big data approach allows us to consider historical, present-day and future habitat distributions and their blue carbon capacity (in terms of sediment carbon storage, sediment accumulation rate, above-ground and below-ground biomass, carbon flux, photosynthetic rate, growth rate, species composition). Utilising habitat suitability modelling and ensemble forecasting allow us to identify: blue carbon storage hotspots, areas at risk of carbon loss and the effects of blue carbon management, habitat restoration and land-use change. By providing a robust knowledge base about the blue carbon potential of the region, we are now using this as the foundation for co-creating actionable steps for a sustainable blue carbon management plan that harmonises local and national priorities for social inclusion, environmental resilience, and economic viability across southeast Asia.