The international mobility of researchers has long been promoted by public funding agencies, yet evidence on its effects remains limited. We study the Marie Skłodowska-Curie Individual Fellowships using data on all applicants to the EU’s Seventh Framework Programme (2007–2013). Exploiting a discontinuity in grant assignment, we identify the causal effects of receiving a fellowship. Grants substantially increase the likelihood that researchers move to their preferred destination. Moreover, grants supporting extra-European mobility, as opposed to those supporting mobility within Europe, raise publication quantity and quality and expand collaboration networks, suggesting higher returns where mobility frictions are larger.