This study explores the complex relationship between migration and secularization in present-day Europe, examining how each transforms, and focusing on post-Soviet migrants in Western Europe since the 1990s to maintain analytic depth. Migration entails both physical movement and the reconstruction of social and religious identities, processes that can support or contest host secular norms. We analyze the formation of novel religious environments, shifts in secularization regimes, and migration’s dual role as both a trigger of secularization and a driver of desecularization. To foreground contemporary dynamics, the article gives dedicated attention to social media and platform-mediated practices. The study advances theoretical understanding of religion–migration–secularism interactions in Europe.