Beach nourishment is a widely used coastal adaptation strategy to maintain or increase beach width, though debate exists as to whether it offers a realistic means to offset projected erosion due to sea level rise. In Port Phillip Bay renourishment has been very successful for maintaining beach character. This study examines whether nearshore-sourced beach nourishment is a viable long-term option for beaches in Port Phillip Bay, Australia. Firstly, the dynamics of beaches were assessed with an intensive drone, hydrographic, sub-bottom sonar and remote sensing study alongside sampling and predictive modelling of sea floor sedimentology. Future shoreline recession was estimated for 1 m sea level rise to 2100, comparing a high-end ‘Bruun-type’ response (more likely on moderate energy shorelines), and a low-end ‘Beachface-type’ response (depth of closure at base of intertidal; more likely on very low energy beaches). It was found that extensive nearshore sandbodies are able to provide a sustainable source of material for beach renourishment. A generalised comparison between long-term nourishment requirements of open coast and bay beaches estimates 40 – 90% less sand is required for bay beaches. Accordingly, managers should be aware of the potential viability of long-term beach nourishment when determining adaptation pathways for estuarine coastlines.