Historiography to date has meticulously examined the domestic trajectory of Japanese citizen activism and movements, yet we still know very little about the transnational history of Japanese activism, and even less about the impact of border-crossing interactions on the activists and groups involved. In this chapter I examine the rich tapestry of transnational Japanese movements focused on Asia from the late-1960s onward and the ways these movements opened the door to new and progressive regionalist visions not previously imaginable within post-war Japanese civic activism. I adopt a transnational historical approach not only as a novel “framing context” for Japanese civic movements but also as a tool to explore the ways cross-border exchanges contributed to ideational changes and thematic developments. Recognition of their multidimensional “aggression” toward Asia – albeit unintentional and by association – motivated some Japanese civic activists to move beyond the rather insular, self-as-victim, focus of many earlier pacifist and environmental movements to a new project both for and with other Asians. Importantly also, many of the transnational initiatives Japanese activists started in Asia endure to the present and continue to shape the mentalities and thematic breadth of Japanese civic activism today.