As hybrid threats intensify and critical infrastructure along Europe’s coasts and seabeds faces increasing sabotage and disruption, the European Union must act decisively to safeguard its maritime and coastal security. Under the umbrella of the European Defence Readiness 2030 and the ‘ReArm Europe’ initiative, Member States are set to debate a legislative proposal aimed at strengthening coordination, capability development, and military mobility in both maritime zones and vulnerable coastal areas. The proposed measures aim to address key gaps in joint surveillance, crisis response, and infrastructure protection, while ensuring coherence with NATO strategies and respecting national sovereignty. As transatlantic relations continue to strain, particularly with the United States’ strategic pivot away from Europe, the question of EU strategic autonomy grows more pressing. Can the Union move toward a unified approach to defending its maritime and coastal frontiers, or will diverging national interests and fragmented capacities continue to hinder collective action?