There is much debate on the sustainability of (generous) welfare systems in the context of freedom of movement within the European Union (EU), often assuming that migrants’ welfare access is only regulated by national borders. In this chapter the authors analyse how and to what extent this assumption is accurate. They use large-scale population data from the Netherlands as a case study for analysing the migration patterns and labour market status of Polish and Bulgarian migrants after these countries joined the EU. Their findings do not support the political and scientific discourse that pressures on generous welfare systems increased due to the 2004 and 2007 EU enlargements. In practice, individuals’ welfare access in the context of free mobility of EU migrants is largely determined by national eligibility criteria tied to their lifecourse stage, labour market status and length of stay in the country. The authors’ findings point to the importance of including lifecourse characteristics for the study of migration and the welfare state.