The substantial importance of cultural benefits as a source of human well-being is increasingly recognised in society-environment interactions. The integration of cultural ecosystem services (CES) into the ecosystem services framework remains a challenge due to the difficulties associated with defining, articulating and measuring CES. We operationalise a novel framework developed by the UK National Ecosystem Assessment that identifies CES as the interactions between environmental spaces (i.e. physical localities or landscapes), and the activities that occur there. We evaluate the benefits of the CES provided by 151 UK marine sites to recreational sea anglers and divers, using subjective well-being indicators. Factor analysis of an online questionnaire with 1220 participants revealed multiple CES benefits that contribute to human wellbeing e.g. including ‘engagement with nature’, ‘place identity’ and ‘therapeutic value’. In addition to regional differences, we also found that biophysical attributes of sites, such as the presence of charismatic species and species diversity, were positively associated with provision of CES benefits. The study provides evidence that could be used to inform designation of protected areas. The indicators used in the study may also be adapted for use across a range of marine and terrestrial spaces for improved integration of CES in environmental decision-making.