This introduction together with the whole special issue on border technologies challenges the limitations of potentially simplistic understandings of contestation, disputes, and political intervention inherent in many accounts of material politics. How do border technologies turn borders into a contested space and how do they come to matter for specific affected communities, especially migrants? How do border technologies manifest hegemonic border-control regimes and thereby marginalise their contestations? Or else, how do they open up alternative versions of the border? Simplified notions of material publics assume that controversial issues may easily turn public. They are also too narrowly framed within the logics of the nation state, de jure citizenship, and specific political articulations of contestation as legitimate within representative democracies. Therefore, these notions disregard opaque, non-transparent forms of government as they are in place through border control regimes, on the one hand, and other less visible forms of contestation deriving from migrant issues and struggles as non-citizens, on the other hand. Migrants concerned with these issues are already marginalised population groups in the context of border technologies. They potentially struggle to make public issues of concern among a wider audience. The introduction together with the special issue expands the analytical repertoire, first, to understand forms of (im)possibilities of contestations related to border technologies and how they are co-shaped by socio-material and epistemic conditions; and second, to include less visible types of material politics, as contesting articulations may appear differently and remain only partially known to wider publics.