The European Union (EU) has modest but promising capacities to assist member states overwhelmed by disaster through its Civil Protection Mechanism. The EU also routinely sends civil and military missions to hotspots outside EU territory. But these capacities do not suffice in the face of transboundary crises: threats that cross geographical and policy borders within the Union. Examples include epidemics, financial crises, floods, and cyber terrorism. Nation states cannot cope with these threats without international collaboration. In this article, we explore the EU's efforts to develop transboundary crisis management capacities. We describe these budding capacities, explain their policy origins, and explore their future potential.