Research on European trade unionism has discussed whether the tendency towards ‘union diplomacy’ has meant that that unions are largely disinterested in mobilizing members and pursue contentious action at the European level. Other studies have identified activities that suggest an Europeanization of political mobilization, in demonstrations and strikes and in cooperation with NGOs and social movements. The present paper analyzes attitudes towards transnational action among trade unions in Europe, as well as the degree to which national unions actually partake in more and less contentious action. The study, which is based on a survey to trade unions in Europe carried out in 201011 (n 250), focuses particularly on the production of joint statements and petitions, demonstrations and boycotts, and strikes. The aim was to identify the similarities and differences between industrial relations regimes and sectors in Europe and the analyses have revealed that there are in fact significant differences. Trade unions in the continental social partnership regime and the southern polarized/state centered regime tend to approve of and partake in European demonstrations and boycotts to a higher degree than unions in the other regimes, while the Nordic unions in the organized corporatist regime tend to be more skeptical and also participate to a lower degree. In addition, unions in services and organizing professionals tend to partake and approve of such action to a lower degree than unions in other sectors and national peak level unions.