The welfare state was constructed to ensure the well-being of a sedentary population, consisting of citizens living within the territorial boundaries of the nation. However, mobility patterns change, and more people lead lives that criss-cross national borders while drawing on different sources of transnational social protection – the welfare state included. Now, the daily work of bureaucrats involves delivering national social security benefits to transnationally mobile recipients. Through encounters and casework processes, these welfare state bureaucrats observe how ‘transnationals’ deal with complex regulations and make use of the social security system. This article explores bureaucrats’ perceptions of individuals’ agency and behaviour as they reconcile their transnational mobility with national social security. It builds on data collected during ethnographic fieldwork in the Norwegian welfare administration, including 36 interviews, participant observation and informal conversations. The analysis identifies an institutional perspective of transnationals’ agency as shaped by their level of regulatory awareness and compliance. The bureaucrats observe some types of transnational behaviour to be more prevalent than others. As the article concludes, these bureaucratic perspectives have major implications for transnational social security delivery and how the welfare state accommodates transnational mobility.