This study is part of a global study on the costs of adaptation to the effects of climate change. It adds information from three specific case studies (the Netherland, New Orleans and Vietnam) to the global study. The case study areas are comparable by type of coast; all are low-lying deltaic coastal areas. This study investigates the unit cost estimates of coastal defence for the full range of hard and soft engineering measures, such as dikes/levees, sea walls, (beach) nourishments and other measures, for example storm surge barriers. In considering the costs of coastal defence and adaptation to climate change different scale levels can be recognized. At the highest level of detail specific information from actual projects and designs can be utilized. This requires detailed insight in the actual design and as built status of coastal defence projects. By combining information from individual projects, cost estimates can be provided for one enclosed coastal defence system, e.g. a dike ring or polder in the Netherlands or New Orleans. Cost estimates at a national level can be obtained by aggregating information from different defence systems. For example, Kok et al. (2008) report estimates of the costs of adaptation of the flood defences in the Netherlands to different levels of sea level rise. This is done by combining assessments of the response of different sub systems and dike rings to the sea level rise. Finally, estimates for different systems and countries can be aggregated to cost estimates at a regional, continental or even global level.