New markets are key in debates concerning environmental regimes. Critics and proponents share a discourse that characterises environmental markets in terms of scale; many discuss how to scale environmental markets `the right way'. Building on previous work in human geography, actor--network theory, and governmentality studies, we unpack the dual but always interwoven politics of scale-making in doing environmental policies, which consists of material-semiotic practices of producing and using scales as ontologically real ordering devices. Drawing from the results of three studies conducted independently by the authors, we analyse material-semiotic scale-making practices in different ways of enacting environmental markets. By revealing the dual politics of scale production and use in environmental markets, our analysis contributes to the study of developing and implementing environmental governance.