Fibre reinforced composites are widely used in marine structures, from small boats to tidal turbines. However, there are some specific features of the marine environment, notably continuous contact with seawater and hydrostatic pressure loading, which require special attention during material selection and design. This paper first describes test procedures developed over the last 30 years to address these conditions in order to identify and validate lifetime prediction models. Surface vessels and underwater applications are discussed. Then, considerations for future applications are described, with particular emphasis on sustainability and environmental impact.