The AEJ (Euroregional Youth Assembly) strengthens innovative cross-border governance in the Pyrenees-Mediterranean Euroregion (Catalonia, Balearic Islands, Occitania) and offers young people a structured space for civic participation. Through mobility, training, workshops, and virtual activities, it enables them to co-create policy proposals, engage with decision-makers, and assert their role as key actors in European integration. AEJ fosters a lasting sustainable Euroregional dynamic and provides a replicable model for other territories across Europe. Goals: -Enhance youth participation in cross-border governance via structured dialogue with institutions. -Build skills in leadership, advocacy, project management, and intercultural communication. -Deliver transferable tools (methodological kit, videos, policy recommendations). -Support the EU Youth Strategy: participation, inclusion, sustainability, transnational cooperation.