In recent years, the global financial crisis and the European and domestic austerity measures which followed have resulted in drastic cuts to public services, heavy job losses and reduced incomes across Europe. In addition, the current refugee crisis has put the European and national asylum systems under strain. At the same time, new protest movements and innovative practices of transnational solidarity have emerged in response to these crises, driven by ordinary citizens and new or re-energised networks of cooperation amongst civil society actors (e.g., NGOs, churches, welfare associations, grassroots initiatives, and so on). This paper investigates and critically analyses the initiatives and practices of Transnational Solidarity Organizations (TSOs) by combining qualitative and quantitative analyses within a comparative approach. Pursuing a distinct research framework, the analysis builds upon the comparison of three countries which are diverse from a social, political and economic standpoint: Italy, the UK and Germany. In this regard, the paper uses selected media sources – primarily hubs, websites, and Facebook pages – in order to map and analyse civic practices and measures aimed at mobilising protest and generating transnational solidarity in three thematic areas, namely disabilities, unemployment and immigration. Finally, our discussion will focus upon the policy implications and lessons to be drawn when aiming at the sustainability of transnational solidarity networks amongst European civil society actors with a particular emphasis on the challenges associated with translating such lessons between diverse European contexts.