This article aims to further understand conflict resolution in Colombia by analysing a topic that has thus far been largely neglected in scholarly analysis: international mediation. It explains that third parties have been involved for three decades, given different roles, and have been more or less accepted by both non-state armed groups and the government. The paper focuses on peace processes between the Colombian government and the oldest and largest guerrilla groups: the Revolutionary Armed Forces of Colombia – People’s Army (FARC-EP, hereafter FARC) and National Liberation Army (ELN). Understanding past initiatives is necessary in order to comprehend and support the current peace talks between the government and the FARC, in which third states are involved. Employing Carl von Clausewitz’s conception of the relationship between the “aim”, the “ultimate objective” and the “means” helps to assess the international contribution to peace negotiations. On the one hand, the article examines the interests of the parties to the conflict, as these are the factors that define foreign intervention. On the other hand, it studies the approach and methods of mediators to assess their strengths and weaknesses. It concludes that the interest of the parties to the conflict was often to have an international presence and ongoing negotiations for the sake of legitimacy, rather than to reach a final peace agreement. This resulted in serious limitations to the third parties’ mandate.