Complex sandy coastlines, such as capes and spits, are important socio-economically while underpinning and protecting important natural habitats. Although they may protect inshore areas, they are inherently fragile and susceptible to erosion. We have explored how spits and capes might adapt to changing wave climate through modelling. We find that coastlines may not be in equilibrium with current conditions, and past shapes may strongly influence those adapting to new wave climates.