The historical link between labour and welfare is increasingly considered in the transnational register, largely because labour mobilities demand a rethinking of nation-based social protection systems. Transnational labour mobilities also illuminate other dimensions of boundary-crossing, including formality–informality, citizenship–non-citizenship and production–reproduction. These additional considerations call for going beyond the problem of transnational welfare access. We argue that the prism of social reproduction enables such a rethinking of the labour–welfare relationship. In this article, we conceptualise an expanded notion of welfare as flourishing social reproduction, in contradistinction to the principle of welfare deriving primarily from paid work and labour market participation. We apply this theorisation of welfare to our qualitative case study of the experiences and interests of Polish and Ukrainian migrant workers in Germany, Poland and the United Kingdom employed in care provision, food production and housing construction sectors. In the geopolitical setting of uneven and combined Europe, embodying high levels of differentiation together with advanced transnational social protection, we explore the role of differentiation of migrants in labour markets (along work, migration and citizenship axes) and the extent to which transnational mobility facilitates the improvement of social reproduction. While the low-waged labour of Polish and Ukrainian men and women working in care, food and housing furnishes their own and local workers’ social reproduction needs, we find that migrant workers’ welfare as flourishing social reproduction remains wanting, even for those with already privileged access to the current ‘gold-standard’ transnational social protection offered by the EUs freedoms of movement framework. Welfare remains centred on individualised paid work logic, leaving a vast range of needs unmet and work and workers excluded, bearing implications for prevalent transnational social protection efforts.