This article details the results of a social survey concerning “depolderisation”, conducted in the Arcachon Bay on the south-western French Atlantic coast. Depolderisation consists of reopening polders to the sea via tidal gates, creating breaches in the dikes or dismantling them altogether. Although this technique has rarely been used in France, in comparison with the UK or the USA, it has begun to arouse interest, especially in the wake of storm Xynthia which in 2010 heavily damaged the French Atlantic reclaimed coast. In the Arcachon Bay, researchers have demonstrated that managing flooding risk through depolderisation leads to ecosystemic benefits, such as a more flexible sea defence through the restoration of saltmarshes, biodiversity enhancement and nature-based recreation. They have also investigated the social acceptability of depolderisation – the main topic of this article. Several methods were used to analyse this acceptability: thorough interviews, a questionnaire survey answered by 675 polder users and inhabitants and a survey on their willingness to pay. The results show that the local people and some of the stakeholders are largely opposed to depolderisation, preferring the reinforcement of sea dikes. This refusal is not linked to a fear of the sea but to a deep attachment to local polders and their uses, and to the slow pace of national policy development on coastal risk management. The fact that similar results have been obtained in other European countries confirms some of these results. This article is a contribution to the debate initiated in developed countries on more flexible or natural ways of managing coastal risks and adaptation to climate change, and on the social obstacles that hinder renewed and sustainable coastal policies.