ABSTRACT By examining how Turkey has strategically leveraged its immigration detention practices in its relationship to the EU, this article draws scholarly attention to the neglected international dimensions of detention policy-making. While narratives of national security bolster the justification for detention of asylum seekers and other migrants, this article focuses on additional roles that Turkey calls on detention to play in its relationship with the European Union. In particular, the article discusses ‘transit migration’ as a policy discourse Turkey has strategically adopted and leveraged to its advantage when dealing with the EU. As form of ‘premature labelling’, this discourse undermines the claims of belonging that foreign nationals labelled as transit migrants have in Turkey. Thus, it provides a narrative for justifying detention expansion. This international dimension of detention policy-making must be taken into account for future discussions around how to curb or abolish the practice at the borders of Europe and elsewhere.