In response to the humanitarian crisis of 2015, Sweden introduced ‘temporary’ border controls. The increasingly permanent controls warrant critical assessment and raise urgent questions: How is border security exercised in practice? What is the relationship between intent and practices on the ground? Which logics drive the border control? This study explores these questions through in-depth interviews with border guards and ethnographic field observations conducted at Hyllie station. Applying Foucault’s concept of biopolitics and Walters’ image of the border-as-firewall, the study critically probes the practices of border security and the logics that underpin it. The study argues that the Swedish border control acts as a (biopolitical) firewall. Yet, this conceptual framework alone cannot account for the multiple logics, rationalities, and objectives that intersect and drive the project of border control. The analysis suggests that biopolitics frames security as a rather monolithic, omnipotent performance of overarching state objectives. In reality, the exercise of border control is assembled ad hoc, constrained by the limits of available resources of the Swedish police and mediated by the agency of individual border guards. Finally, the study reflects on the exclusionary logic embedded in the practices of border control and stakes out paths for future research.