This paper draws on a novel database of 360 collective transnational socioeconomic protest actions across Europe that we found in a comprehensive, multilingual set of labour-related news outlets from 1997 to 2020. We discovered that the number of transnational protest actions doubled from 61 (1997–2002) to 125 (2015–2020). This is surprising, as unions seemed to be retreating everywhere. This study assesses two explanations for this development – one related to the economic, the other to the political, European integration process. Our findings suggest that exposure to horizontal market pressures in the ever-more integrated European economy cannot alone explain the rise in collective transnational protest actions. Rather, our figures indicate that increasing vertical political pressures triggered by commodifying policy interventions of EU authorities play a pivotal role in driving transnational collective action, thereby highlighting the importance of politics in European industrial relations and transnational collective action.