Border regimes are pervaded by moral economies that justify practices of regulation and control. This article attends to the moral economies that animate migrants’ struggles and related practices of subversion. Based on a reading of moral economies close to E.P Thompson’s original formulation of the concept, it investigates the norms and beliefs that are carried by migrants’ practices of appropriation. By showing that these practices are, from migrants’ viewpoint, just and legitimate insofar as they defend or restore traditional rights, customs and entitlements, the analysis destabilizes dominant framings of migrants as cunning tricksters. Moreover, the analysis of the moral economies of migrants’ border struggles allows to distinguish between two different logics of appropriation. To this end, I mobilize two figures of thought from postcolonial theory. First, Homi Bhabha’s notion of mimicry captures the logic of practices that repurpose mechanisms of control in ways that allow migrants to obtain a visa, asylum, or a residency title (subversion through documentation). Second, Eduard Glissant’s work on opacity enables us in turn to theorize practices of appropriation that rely on the creation of ambiguity and multiplicity to counteract authorities’ attempts to assign migrants a unique stable identity by means of biometrics (subversion of documentation).