This article examines the relationships established between left-wing organizations active throughout the 1960s and 1970s on both sides of the Atlantic: the Partido Revolucionario de los Trabajadores – Ejército Revolucionario del Pueblo (PRT-ERP) and the Partido Revolucionário do Proletariado – Brigadas Revolucionárias (PRP-BR). The trip to Lisbon, in March 1975, of a delegation of Argentine militants serves as the guiding thread that allows us, throughout the text, to analyze the political horizons and objectives that fostered the creation of material and symbolic connections among activists operating in different contexts across Europe and Latin America. In this sense, we argue that exchanges among these actors encouraged significant transformations in their viewpoints and in their analyses of the international revolutionary context, and consequently helped shape their political practices on the ground. Finally, by shedding light on an experience that has been largely unexplored in the historiography, the article highlights the depth and multidirectional character of the transnational connections that contributed to shaping the emancipatory projects that emerged throughout the second half of the twentieth century.