In the last decades the terms 'Christianity' and 'migration' have often been appropriated and represented in antagonistic terms by individuals and formations on the far right of politics. Yet, believers and institutions from the Catholic Church, as well as various other Christian denominations, have been behind considerable activism in support of migrants and refugees. Not only do they provide services to migrants and refugees but also, and most importantly, they are active in this post-secular public sphere leading campaigns advocating for the rights of migrants and refugees and condemning the 'hostile environments' put in place by various governments, as well as the criminalisation of irregular migration. Among the various Christian denominations, the head of the Catholic Church, Pope Francis, is perhaps the most prominent - but not the only - leading religious figure speaking out for human dignity and a more humane border system. Increasingly, the Catholic church (by this I mean institutional leaders and communities as well as individual lay members) and an array of faith-based non-governmental organisations (FBOs) are engaged in ecumenical and also interfaith collaborations around these issues. Thus practical and conceptual resources are being developed to revive a welcoming democratic tradition and to withstand the anti-immigration illiberal trends that are clad in Christian terminology. Drawing on empirical materials of pro-migrants Catholic and other Christian denominations' activism from various European countries and institutions, the paper examines whether and in what ways an ecumenical political theology (and not yet another Christian narrative) is being developed and the significance it has for reconsidering the role of Christianity, and of religion more broadly, in the European public sphere, in relation to the project of European integration and in world politics. ultimately this considers the changing role of the Catholic church in global politics.