SUPERFLOW will determine the pathways and dynamics of dense water in the Nordic Seas that sustains the lower limb of the Atlantic Meridional Overturning Circulation (AMOC), which helps maintain the temperate climate of northwest Europe. The densest water supplying the AMOC stems likely from the Greenland Sea and crosses the submarine Greenland-Scotland Ridge through deep passages east and west of Iceland. While the exchange flows across the ridge have been monitored for several decades, the circulation and partitioning of the upstream flows that are co-located northeast of Iceland are not yet quantified and understood. Advancing this understanding is imperative for an accurate prediction of how the AMOC will respond to a changing climate. To identify the sources and quantify the transports of these dense-water pathways, and to understand their dynamics, a unique combination of unpublished two-year long observational time series northeast of Iceland with a high-resolution, realistic simulation from an ocean model and an idealised two-layer model will be used. The importance of this deep circulation for climate will be advertised to pupils and science-interested citizens through a coherent outreach package. SUPERFLOW will accelerate the academic career of a promising young female scientist by providing an opportunity to train scientific, outreach, and transferable skills. While the host institution is the University of Bergen (Norway), a 21-month appointment at the world-renowned Woods Hole Oceanographic Institution (WHOI) in the USA and a three-month secondment at the Marine and Freshwater Research Institute (MFRI) in Iceland are planned. This mobility is key to the success of the project, which will maintain Scandinavia’s position at the forefront of research in the North Atlantic.