# Southeast Europe regional cooperation and infrastructure

> Live situation record from CLSTR: https://clstr.news/situations/southeast-europe-regional-cooperation-and-infrastructure
> Updated: 2026-09-06T13:07:22.000Z. Sources: 11. Developments: 4.

Regional cooperation in Southeast Europe is advancing through new institutional frameworks and infrastructure initiatives. In late August 2026, Romania, Moldova, Ukraine, and Bulgaria announced plans to form the ‘EAST GATE’ European Grouping of Territorial Cooperation to facilitate cross-border projects and European integration.

Building on these connectivity goals, Greece, Bulgaria, and Romania have signed a memorandum of cooperation to develop a strategic transport megaproject connecting the Aegean Sea and the Black Sea. Announced by European Commissioner Apostolos Tzitzikostas, the project involves constructing and modernizing road and rail infrastructure along the Thessaloniki–Sofia–Bucharest route. Speaking at the 90th Thessaloniki International Fair, Tzitzikostas emphasized that the corridor could redefine the region’s geostrategic importance by enhancing trade, exports, and security, potentially transforming Greece into the “southern gateway to Europe.”

The corridor has a 15-year implementation horizon and is designed to provide a terrestrial alternative for the movement of goods and people, reducing sole reliance on the Bosporus and Dardanelles straits. While the route is intended to extend toward Central and Western Europe, eastward connections are expected to link to Moldova and Ukraine.

Bulgaria serves as a central link between Greek ports, Romania, and the broader European network. Funding of 277 million euros from the Connecting Europe Facility has already been secured for the 68.3-kilometer Alexandroupolis–Pythio railway section. Additional funding for remaining sections is expected to be announced in the coming months. This corridor is part of the Trans-European Transport Network (TEN-T) under the Baltic Sea–Black Sea–Aegean Sea direction.

## Timeline

### 2026-09-06: Greece, Bulgaria, and Romania launch Aegean-Black Sea transport corridor

Greece, Bulgaria, and Romania are launching a 15-year transport megaproject to link the Aegean and Black Seas via a new Thessaloniki–Sofia–Bucharest corridor.

3 sources. https://clstr.news/cluster/greece-bulgaria-and-romania-launch-aegean-black-sea-transport-corridor

### 2026-09-06: Thessaloniki-Bucharest transport axis to link Greece with Eastern Europe

Commissioner Apostolos Tzitzikostas announced a strategic road and rail axis connecting Thessaloniki to Bucharest to turn Greece into Europe's southern gateway, alongside a new EU tourism policy.

2 sources. https://clstr.news/cluster/thessaloniki-bucharest-transport-axis-to-link-greece-with-eastern-europe

### 2026-09-03: Bulgaria, Romania, and Greece plan joint transport infrastructure projects

Bulgaria, Romania, and Greece are planning joint transport infrastructure projects to link the Aegean, Black Sea, and Danube regions, focusing on economic connectivity and military mobility.

4 sources. https://clstr.news/cluster/bulgaria-romania-and-greece-to-submit-joint-infrastructure-projects

### 2026-08-26: Romania, Moldova, Ukraine, and Bulgaria to form EAST GATE cooperation grouping

Local authorities from Romania, Moldova, Ukraine, and Bulgaria will sign founding documents for the “EAST GATE” European Grouping of Territorial Cooperation in September 2026 to foster regional integration.

2 sources. https://clstr.news/cluster/romania-moldova-ukraine-and-bulgaria-to-form-east-gate-cooperation-grouping

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Cite as: Southeast Europe regional cooperation and infrastructure. CLSTR, https://clstr.news/situations/southeast-europe-regional-cooperation-and-infrastructure