A massive tunnel project is currently in progress to link Europe and Asia, designed to accommodate around 1.3 million daily travelers with multiple levels for cars and trains. This transportation link spanning 6.5 km (4 miles) in Istanbul is estimated to cost £2.8 billion and is set to open in 2028.
Dubbed The Great Istanbul Tunnel, the initiative reflects Turkey’s significant investment in enhancing its transportation infrastructure to bolster the domestic economy. Situated beneath the Bosphorus strait, a crucial 30-km waterway connecting the Black Sea and the Sea of Marmara, the tunnel will serve as a key link between the two continents, Europe and Asia, within Istanbul, a city straddling both regions.
Upon completion, The Great Istanbul Tunnel will be the third underwater tunnel beneath the Bosphorus, following the Marmaray Tunnel (3.5km) and the Eurasia Tunnel (5.4km). The ongoing construction utilizes one of the largest tunnel boring machines in the world, measuring 83m in length and 20m in width.
Positioned 110 meters below sea level, the tunnel will feature an 18.8-meter diameter to accommodate both cars and trains. With plans for a three-tier structure, two levels will cater to cars while the third will be designated for trains. This development will seamlessly connect Istanbul’s major airports and 11 railway lines, optimizing the functionality of the Metrobus system, a critical component of the city’s transport network.
The railway segment of The Great Istanbul Tunnel will encompass 13 stations, capable of handling 70,000 passengers per hour in a single direction. This integration with existing railways and the Metrobus line aims to reduce travel times across the Bosphorus to just over 40 minutes, as stated by Minister Karaismailoğlu.
The primary objective of this project is to foster trade and tourism between Europe and Asia, generate employment opportunities, and stimulate economic growth in Turkey. Moreover, by alleviating traffic congestion in Istanbul, the tunnel is expected to enhance the residents’ quality of life and mitigate environmental pollution.
First announced by Prime Minister Ahmet Davutoğlu in 2015, the scheme aims to address the increasing demand for crossings between the European and Asian sides of Istanbul. With projections indicating a future daily crossing volume exceeding three million, the tunnel project is a strategic response to the current daily traffic surpassing two million.
