Providing an overview of the emergence, characteristics, trajectory, and potential limitations of the transnational anti-base network, this article focuses on two broad questions relevant to transnational politics. First, what processes and mechanisms enabled local and transnational activists to form the international No Bases network? Second, how did activists juxtapose existing local anti-base identity and frames to emerging transnational ones? Following existing transnational movement theories, I argue that the global anti-base network slowly emerged through processes of diffusion and scale shift in its early stages. The onset of the Iraq War, however, injected new life into the transnational anti-base movement, eventually leading to the inaugural International Conference for the Abolition of Foreign Bases in 2007. Although loose transnational ties existed among anti-base activists prior to 2003, the U.S. war in Iraq presented anti-base activists the global frames necessary to accelerate the pace of diffusion, scale-shift, and brokerage, and hence, the consolidation of a transnational anti-base network. Paradoxically, however, even as No Bases leaders attempted to forge a new transnational identity, anti-base activists, as “rooted cosmopolitans,” continued to anchor their struggle in local initiatives.