Since the end of January 2020 and the first cases of COVID-19 in Europe, the Schengen member states have been operating in a rapidly changing environment. In an attempt to limit the spread of the epidemic, they have introduced temporary border controls and travel restrictions within the Schengen area with little to no coordination. The economic, social and political costs of these unilateral measures are putting a heavy strain on the Schengen system and its member states. The absence of a joint response could have a long-lasting impact on the Schengen project and, more generally, on European integration.