Globally, it is widely acknowledged that constructing hard engineered coastal defences is both financially and environmentally unsustainable. Here we seek to investigate the willingness of residents in rapidly eroding coastal zones to contribute towards the costs of constructing and maintaining such structures. The originality of this paper is that it provides one of the first analyses of the influence of social capital parameters (social trust, institutional trust, social reciprocity and social networks) on respondents' willingness to pay (WTP). Fieldwork for the study was conducted in Romney Marsh, a low-lying coastal area of south-east England. The findings have substantive public policy implications for coastal management. First is that we demonstrate that while social and institutional trust exerts a positive influence on WTP, the presence of social networks militates against WTP. Secondly while the study found 45.6% of respondents were willing to pay an average monthly premium of £3.53, a high level of refusal to pay was evident among respondents. Thirdly even among those respondents willing to pay, disagreement was expressed over the political–administrative level at which a ‘coastal defence tax’ should be collected.