Highly mobile workers challenging Regulation 883/2004: Pushing borders or opening Pandora’s box?

This research paper aims to highlight hurdles that EU citizens may encounter when exercising their social security rights while working across borders. With the focus on the worker who is highly mobile in the sense of performing various work activities in two or more Member States, the paper analyses how the current system of coordination copes with the increasing mobility in the European labour market. On the basis of an illustrative case, it demonstrates where and explains why high mobility leads to legal and practical ambiguities due to the different interpretations of the rules determining the applicable law, particularly Article 13 of Regulation 883/2004.