Vulnerability has emerged as a central policy concept in migration governance. Despite its growing importance, the concept remains contested and ambiguous. As multiple notions of vulnerability circulate in the context of migration and asylum governance, it becomes crucial to gain a better understanding of how vulnerability might shape practices on the ground. In this article, I explore how different actors in the province of Cádiz, located at Spain and EU’s southern maritime border, understood, and operationalised ‘vulnerability’. The aim is to advance understandings of vulnerability as a mechanism of governance in the reception of people on the move in the context of so-called ‘mixed movements’. My focus is as such on the interplay between the concept of vulnerability and the conceptual distinction between asylum seeker/ political refugee and irregular/economic migrant. Through the analysis, I show how attempts to define and prioritise forms of vulnerability was constantly changing. For actors on the ground, the vagueness of the notion of vulnerability thus constituted a continuing on-the-ground challenge as well as an opportunity to challenge categorical and legal distinctions. Still, civil society organisations’ engagement with vulnerability did not only represent a ‘push-back’ of restrictive policies, but also a way to adapt and survive in a marketised regime.