Within the broader theme of Latin American migration to Europe, this article looks at the less explored case of Colombian migrants in the United Kingdom and Spain. More specifically, it focuses on the transnational political activities of these migrants in connection with the armed conflict and search for peace in Colombia, a case of “diaspora politics” that has not received much attention. It is based on research into the wider transnational political linkages of Colombians in these two countries conducted during 2004–2007. This research involved nearly 100 semi-structured interviews with Colombian men and women who had migrated for political, security, labour and other reasons, as well as interviews with experts, participant observation and analysis of online community forums and other materials. As such, this study went beyond the dominant focus on economic migration. This approach helped to shed light on an aspect of Colombian migrant transnational politics hardly taken into account before, that is, the individual and collective activities that deal with the violence, human rights situation, and search for peace in Colombia. The first part of the article offers a summary of the conceptual and methodological issues underpinning this research and a description of the most relevant characteristics of the two migrant communities studied. In the second part, the article analyses the evidence gathered on Colombian migrant transnational activism in relation to the armed conflict and search for peace in Colombia and the potential and limitations of this work. The aim of the article is two-fold: to enrich the pool of knowledge on Latin American migration to Europe and to engage with recent literature on the role that diasporas and transnational communities play in relation to conflict in their home countries as part of diasporic or transnational civil society.