Recent years have seen considerable increases in the number of internationally-qualified social workers in England. This article presents trends in the international labour mobility of social workers migrating to work in England alongside information on the supply of UK-trained social workers. It concludes that demographic changes and policy imperatives have accentuated structural issues making it difficult to ensure an adequate supply in the number of domestically-trained social workers. We suggest that more cross-national research is needed to achieve a better understanding of the factors influencing social workers’ decisions to work in international settings and the extent to which this reflects permanent or temporary migration between countries.