The article investigates the role of the International Organization for Migration (IOM) in the global migration regime against the backdrop of the European Union (EU) border externalisation process in Niger. Over the last few years, UN agencies have been considered an essential component of the EU strategy to prevent irregular migrants from reaching Europe. Drawing on qualitative research and ethnographic fieldwork, combining empirical observation with critical analysis, we explore the ‘humanitarian–security nexus’ by focusing on the IOM's ‘humanitarian borderwork’ under the financial umbrella of the Emergency Trust Fund for Africa (ETFA). While the results of purely securitarian measures in Niger may have been ‘disappointing’, the outsourcing of migration management through IOM balances the interests of the Nigerien government and the EU. By focusing on IOM humanitarian operations and assisted voluntary returns and reintegration (AVRR) programmes, the article shows the further expansion of European humanitarian borders into the heart of the Sahel, highlighting new interdiction practices, hidden forms of deportation, side effects and contestation from below.