This paper presents key findings of a recently completed socio-legal study of international retirement migration in the European Union (EU). It highlights the diverse nature of retirement migration and the differential citizenship status that is formally granted to various groups of retired migrants. ‘Citizenship of the European Union’ (Articles 17–22 of the Treaty establishing the European Community) bestows important social and political rights on nationals of EU Member States (‘Community nationals’). These rights are not, however, universal or based on nationality as such. In practice, the residency and social rights that a mobile EU national can claim in another Member State depend on the type of social contribution they have made and their personal relationships. Contributions through paid employment and/or membership of the family of a mobile EU worker gives rise to maximum social benefit. Whilst the European Union citizenship provisions extend residency rights to all EU nationals (irrespective of work status), those whose mobility is not connected to employment derive significantly inferior social entitlements when resident in a host Member State. Put simply, the rights of people (and members of their family) who move following retirement in their home country differ substantially from those who retire following a period of working in another Member State (and achieve the status of ‘community migrant worker’ prior to retirement). This formal ‘discrimination’ is further compounded by the diversity of the social welfare systems of the member states that results in distinct social, economic and spatial inequalities across the EU. To that extent, the ‘choice’ of retirement location significantly impacts on citizenship status. However, retired migrants are not merely passive spectators of formal rights and policies. Many show considerable skill in actively managing their rights (at both national and EU levels) and other resources to optimise personal benefit. This ability to maximise wellbeing is unevenly distributed.