The 2019 European Parliament elections seemingly fostered concerted political action among radical right parties (RRPs) to fortify their positions and mobilize publics on a pan-European scale. Digital platforms provide central infrastructure for networks among political actors and user interactions on the ground. Our study, therefore, investigates the intra- and transnational networking on Twitter established by RRPs’ strategic communication and user interactions. To understand how distinct political and media-related opportunity structures align with different intensities, types, and meanings of digital connections, we investigate the salience, actor types, and geographical scopes as well as the functions of digital connections within and across Twitter networks in Austria, France, Germany, Italy, Poland, and Sweden during the EP election campaigns. Our results indicate the influence of parties’ structural power position on networked communication: The ecologies around RRPs in government reflect their integration in national discourses and competition. The networks of RRPs in opposition display a self-referential campaign ecology for the promotion and distribution of candidates, content, and positions. Transnationality in these networks is structured by EU-level collaboration and driven by civil society and political entrepreneurs, who appear keener to mobilize across borders.