Bulgaria, Greece, Romania, and the European Union signed a cooperation agreement to create and develop the Black Sea–Aegean Sea cross-border transport corridor. The project envisages the development of a north–south route in southwestern Europe using inland waterways, primarily the Danube River, rail and road infrastructure, sea and air ports, and multimodal terminals. The new route will become part of the TEN-T trans-European transport network.
The corridor will consist of three branches. The western line will pass through Athens, Thessaloniki, and Promachon in Greece, then through Culata and Sofia in Bulgaria, connecting Craiova and Bucharest in Romania. The central line will connect Thessaloniki and Alexandroupoli with Ormenio in Greece, Svilengrad and Ruse in Bulgaria, as well as Giurgiu, Bucharest, and Siret on the Romanian border with Ukraine, with access to Ungheni on the border with Moldova. The eastern line will connect Alexandroupoli and Ormenio in Greece with Svilengrad, Stara Zagora, and the ports of Burgas and Varna in Bulgaria, as well as with the port of Constanta in Romania.
The agreement establishes the implementation of cross-border projects in accordance with EU technical standards, including ensuring infrastructure interoperability, implementing the European Train Control System (ETCS), and organizing the operation of freight trains up to 740 meters long on international routes. The project is expected to create an integrated multimodal transport system and ensure seamless border crossings in the region.