Istanbul Airport and Sabiha Gokcen International Airport are set to be connected for the first time by a direct rail line under a $6.75bn financing agreement backed by six international lenders.
Transport and Infrastructure Minister Abdulkadir Uraloglu announced that preliminary agreements have been reached with the World Bank, the Asian Infrastructure Investment Bank, the Asian Development Bank, the Islamic Development Bank, the European Bank for Reconstruction and Development, and the OPEC Fund for International Development. The project, known as the Northern Ring Railway, is expected to carry 33 million passengers and 30 million tonnes of freight annually.
Construction tender preparations are under way, and officials plan to complete the procurement process and site handover within this year. The new railway will start from the Cayirova section of the Marmaray line, pass through Sabiha Gokcen International Airport, cross the Yavuz Sultan Selim Bridge, continue to Istanbul Airport and extend to Catalca. In Catalca, it will integrate with the Halkali Cerkezkoy High Speed Train Line, creating a continuous rail corridor across the city.
Uraloglu said the preliminary financing agreement gives the Northern Ring Railway the status of Turkey’s largest externally financed rail project to date. The total funding package of $6.75bn reflects growing international backing for large-scale transport infrastructure in Istanbul, a city of more than 15 million people and one of the world’s busiest aviation hubs.
The rail connection will unite the two airports on opposite sides of the megacity, linking Europe and Asia by a single dedicated railway for both passengers and freight. Istanbul Airport, on the European side, and Sabiha Gokcen International Airport, on the Asian side, currently rely on road transport and existing urban rail links that do not directly connect the two hubs.
By integrating with Marmaray and the Halkali-Cerkezkoy High-Speed Train Line, the project aims to strengthen national and regional rail connectivity. Officials expect the line to ease congestion on major highways and provide a faster transfer option for travellers moving between long-haul and regional flights.
The route’s inclusion of the Yavuz Sultan Selim Bridge highlights its strategic design as a northern transport corridor encircling Istanbul. In addition to airport transfers, the railway is projected to support cargo flows between logistics centres, ports and industrial zones, reinforcing the city’s role as a key trade gateway between Europe, Asia and the Middle East.
Authorities have not yet announced a construction timeline beyond confirming that the tender process is progressing rapidly. Once completed, the direct rail link between Istanbul Airport and Sabiha Gokcen International Airport will mark a significant shift in how passengers and freight move across Turkey’s largest city.
