Despite the recognised benefits to human health from green and blue spaces, socioeconomic inequalities in access to and use of such spaces have been observed. Using a multidisciplinary, multistakeholder systems approach and structural equation modelling, this paper examines the structural and behavioural dynamics of green and blue spaces, people and health and wellbeing outcomes. Systems thinking offers a deeper understanding of the dynamics of collective choices at all levels within the determinants and the circular causality of these processes. The resulting map shows that behavioural and structural dynamics of green and blue spaces reinforce social cohesion, mental and physical benefits and their circular causality. Acknowledging the importance of multiple uses of green and blue spaces, this paper concludes that delivering universal services at a scale and intensity proportionate to the degree of need is vital to ensure services and health and wellbeing benefits are available to all, not only the most advantaged.