The phenomenon of “crimmigration”—or the convergence of criminal and immigration laws—appears to have a harmful impact on migrants, ranging from increasing negative attitudes about non-citizens to more restrictive immigration policies. This Global Detention Project working paper argues that immigration detention regulated by European Union (EU) directives represents a peculiar manifestation of crimmigration. In particular, detention provisions laid down in the Returns Directive and the recently revised Reception Conditions Directive selectively incorporate criminal justice objectives while rejecting protective features that are provided in criminal processes. Thus, while immigration detention sanctioned by EU directives may pursue objectives similar to those of criminal justice—retribution, deterrence, or incapacitation—detainees are not entitled to due process guarantees afforded to their criminal counterparts. This paper argues that in cases where formally administrative immigration detention is punitive in practice, detainees should be granted broader procedural protections, including presumption in favour of non-custodial alternatives to detention, automatic review of detention, personal hearings, and legal and linguistic assistance.