In Europe, the field of research on welfare state attitudes has ignored the perspective of migrants almost completely. However, welfare systems in destination and origin countries play an important role for migration patterns within and towards Europe. So far little is known on the role of welfare regimes in origin countries on migration aspirations and decisions. At the same time, due to migrants’ socialization in different welfare regimes and their often disadvantaged socio-economic positions, their perspective provides a unique opportunity to test the central theories in the field of welfare regimes. Within the European Union, two developments in particular challenge the welfare state: the transnationalization of citizenship and welfare rights and the judicialization of politics. Here, questions arise on the portability, that is, the transfer and recognition of EU citizens’ social rights who migrate from one member state to another. Projects in the cluster “Migration” address the following questions: How do welfare systems affect mobility patterns in Europe and wat role does transferability of welfare accounts play in mobility across Europe? How do welfare attitudes differ amongst migrant groups and how do they compare to overall public opinion? How have EU member states responded to the transnationalization of welfare rights and the judicialization of politics? And, how do the social rights of mobile citizens manifest in policy and in practice and in which ways do mobile EU citizens experience, organize and manage their welfare transnationally?