Authors Winder and Le Heron (2017) call on geographers to engage in marine policy venues associated with the Blue Economy agenda. This commentary suggests a pragmatic approach, drawing on our human–environment and spatial traditions and bridging positivist and critical constructivist epistemologies. Biophysical attributes of ocean environments create diffuse publics. Examples from fisheries and marine planning illustrate how geographers can lend expertise in scalar and socio-spatial complexity.