Abstract: The inexorable rise of sea levels as a result of runaway global greenhouse emissions is beginning to gain traction as an issue for both the Australian federal government and coastal planning authorities. Whilst various policy mechanisms to regulate future developments are becoming mainstream, existing developments which face an increased flooding or erosion threat remain problematic. Three strategies exist, namely defend, accommodate or retreat, but the appropriate policy choice is dependent on a broad range of factors. Local geomorphology, the value of existing property and infrastructure, community opinion and the legislative background, especially in respect of public liability, all weigh on such policy decisions. We report on research designed to develop a tool to assist local councils make informed policy choices in respect of such vulnerable development. A decision map is developed and explained and tested on case study sites in South Australia. The research demonstrates that the “common sense” strategy of managed retreat may in fact prove the least productive over the next few decades.