Science diplomacy has become an increasingly important component of the European geopolitical toolbox over the past few years. Building on both the 2025 expert report “A European framework for science diplomacy” and the call for evidence, the upcoming Council Recommendation represents a key opportunity for the European Union (EU) to stand for multilateralism in the face of geopolitical upheaval through a comprehensive, inclusive movement of science diplomacy. The EU must navigate significant challenges, including rising tensions and uncertainty, which are leading to the re-evaluation of historical alliances, as well as the politicisation of science, the spread of post-truth narratives, and anti-science rhetoric. The situation is further complicated by the growing number of actors engaged in science diplomacy, each with different interests and time horizons. In this context, the 2nd European Science Diplomacy Conference, organised on 17–18 December 2025 by the Danish Presidency of the Council of the EU and the European Commission, in cooperation with Danish actors, was particularly timely. As part of this major conference, the side event “From research to relation: international scientific networks, the quiet diplomats,” explored how international scientific networks and long-standing research collaborations underpin trust-building and contribute to science diplomacy and global decision-making. Organised by the European Cooperation in Science and Technology (COST) Association, the Marie Curie Alumni Association (MCAA), The Guild of European Research-Intensive Universities, and Université Côte d’Azur, the session aimed to present concrete case studies illustrating these contributions and to engage with the audience.