‘Campaigning in Europe for a Free Indonesia’ explores Indonesian transnational political networks in the late colonial period, connecting the history of Indonesian nationalism with that of anticolonial internationalism and transnational activism. This book adds an international dimension to our understanding of the nationalist and anticolonial movement in the Netherlands Indies. Offering important new understandings of the Indonesian independence struggle, this fine-grained study explores the international activities in the capitals of interwar Europe of the Perhimpoenan Indonesia (PI), an Indonesian nationalist student organisation based in the Netherlands. Operating in a vibrant political environment, the PI interacted with different anticolonial movements in cities across Europe. Focusing on the period between 1917 and 1931, the book follows the personal journeys of different students to cities such as Zürich, Paris, Brussels and Berlin as they established contacts, joined associations and attended international conferences. Here, the complex reality of movement building is examined, going beyond superficial suggestions of contact and collaboration. The study shows that the activities of the PI reverberated in the Indonesian political landscape, where the new collaborations in Europe were followed with great interest. In this way, the book offers new findings for multiple audiences – Indonesianists and scholars of anticolonial resistance alike. However, it also demonstrates that the political awakening of Indonesian elites should be understood not just as an indigenous response to Dutch rule but also as part of global anticolonial movements and struggles.