The scholarly literature on paradiplomacy has tended to focus overly on subnational governments in federal systems rather than those in unitary and centralized countries. However, it is important to note that some subnational governments in these countries have been increasingly proactive in international relations (IR). This study explores the paradiplomatic activities of Yunnan, a province in the south of China which, since the early 1990s, has actively engaged in cross-border cooperation. Combining the concept of paradiplomacy with the theory of actorness, this study first argues that Yunnan has been incentivized to conduct paradiplomacy through the decision of Beijing to open China’s borders; the inefficiency of the central government in managing border-related issues; and the interprovincial competition over economic and diplomatic clouts in the Mekong subregion. Second, this study argues that Yunnan’s new external affairs powers have been consolidated by a host of new opportunities stemming from the external environment. Third, it argues that Yunnan’s new external affairs powers have enabled it to leverage two broad instruments (infrastructure development and economic statecraft) to make neighboring countries more dependent on cooperation with it. And finally, it is argued that Yunnan’s role as an IR player has been acknowledged both by neighboring countries and by Beijing.