The threats that climate-change-induced sea level rise pose to coastal communities can be assessed using coastal vulnerability models. In order to be effective, such models require accurate estimates of shoreline position. Such data are rarely available in developing countries. Here, we develop a simple approach based on image thresholding and subsequent vectorisation of Sentinel-1 SAR data for a complex intertidal zone in the Niger Delta, Nigeria, and show how shoreline position varies over space and time under different tidal conditions.