The coastal and marine environment is often managed according to the principles of sustainable development, which include environmental, economic, and social dimensions. While each are equally important, social sustainability receives a lower priority in both policy and research. Methodologies for assessing social sustainability are less developed than for environmental and economic sustainability, and there is a lack of data on the social aspects of sustainable development (such as social equity), which constitutes a barrier to understanding social considerations and integrating them into natural resource management. This paper explores a threat and risk assessment to the marine estate in New South Wales, Australia, which identified and categorised both the benefits that communities gain from the marine estate and the threats to those benefits. A broad range of benefits were identified including participation (e.g., socialising and sense of community), enjoyment (e.g., enjoying the biodiversity and beauty), cultural heritage and use, intrinsic and bequest values, the viability of businesses, and direct economic values. Threats to community benefits were categorised as resource use conflict, environmental, governance, public safety, critical knowledge gaps and lack of access. An integrated threat and risk assessment approach found that the priority threats to community benefits were environmental threats (e.g., water pollution), critical knowledge gaps (e.g., inadequate social and economic information), governance (e.g., lack of compliance), resource-use conflict (e.g., anti-social behaviour), and lack of access (e.g., loss of fishing access). Threat and risk assessment is an evidence-based tool that is useful for marine planning because it provides a structured approach to incorporating multiple types of knowledge and enables limited resources to be targeted to the threats identified as being most important to address.