This article investigates the making and contestation of mobile borders around the Channel Tunnel, the fixed link connecting Britain and the European continent. It suggests that the bordering of the infrastructural and vehicular spaces is both an object of inquiry in its own right and a productive lens for reflecting on questions related to European Union (EU) territory, the heterogeneous nature of borders as well as the interplay between regimes of control and resistance. The article starts by reviewing the legal and institutional frameworks in which the Channel Tunnel area is governed and envisioned as an interstate and European/Schengen borderzone. It then examines the uncoordinated efforts of national, private and European authorities in managing the episodic migration controversies around this area, which bring together the interconnected rationales of security, economy and humanitarianism and expose the dissonance between and within them. Finally, the article considers how the acts of turbulent mobilities interact with this contingent assemblage of mobility governance and realise the radical potential of territorial borders.