This editorial introduction reflects on a special issue of Territory, Politics, Governance that evaluates water infrastructure and processes of regionalisation through case studies drawing upon the ‘infrastructural regionalism’ framework. This regional approach to the infrastructure turn emphasises: (1) interdisciplinary research; (2) infrastructure and regional governance; (3) ‘seeing like a region’; and (4) regional lives. We outline four dimensions that attend to the regional politics of water infrastructure and introduce the case studies via three unifying themes: representation, mediation and complexity. We conclude by arguing that a regional approach is a necessary and specific spatial lens through which to understand water infrastructure governance.