While some scholars assert that non-state actors (NSAs) can be considered as public diplomacy agents in their own right, others argue that NSAs’ work only supplements a state’s public diplomacy efforts. Both groups of scholars, however, focus on collaboration between states and NSAs. This article draws attention to the situations in which transnational NSAs challenge their respective states. Using the transnational movement Open Russia as a case study and drawing on Robert Kelley’s conceptualization of the diplomatic capabilities of NSAs as manifesting themselves in such actions as disruption, agenda-setting, mobilizing and gatekeeping, this article explores the power interplay between Open Russia and its domestic and foreign constituencies. By analysing the potential and the limits of Open Russia’s diplomatic capabilities, the article expands the discussion about NSAs’ role in public diplomacy.