The risk that tropical storm occurrence may alter as a result of global warming presents coastal managers, particularly in vulnerable areas, with a serious challenge. Many countries are hard-pressed to protect their coastal resources against present-day hazards, let alone any increased threat in the future. Moreover, the threat posed by climate change is uncertain making the increased costs of protection difficult to justify. Here, we examine one management strategy, based on the rehabilitation of the mangrove ecosystem, which may provide a dual, ‘winwin’ benefit in improving the livelihood of local resource users as well as enhancing sea defences. The strategy, therefore, represents a precautionary approach to climate impact mitigation. This paper quantifies the economic benefits of mangrove rehabilitation undertaken, inter alia, to enhance sea defence systems in three coastal Districts of northern Vietnam. The results of the analysis show that mangrove rehabilitation can be desirable from an economic perspective based solely on the direct use benefits by local communities. Such activities have even higher benefit cost ratios with the inclusion of the indirect benefits resulting from the avoided maintenance cost for the sea dike system which the mangrove stands protect from coastal storm surges.