The importance of private insurance to ensure an acceptable level of social protection for mobile EU citizens is still an understudied topic in academia. The need for private insurance within a transnational context in the EU might be particularly important for access to, and reimbursement of, healthcare. Two research questions have been analysed in this study: 1) In which cases of intra-EU mobility and for which groups of mobile EU citizens is there a need for private health insurance? 2) What is the extent of the use of private health insurance within a transnational context in the EU? For the analysis of both research questions, a distinction was made between three types of cross-border healthcare, notably unplanned necessary cross-border healthcare, planned cross-border healthcare, and healthcare provided to EU citizens residing in another Member State. The results could be a stepping stone to defining a multidisciplinary research agenda.