The Beylerbeyi Palace Tunnel, built between 1829 and 1832 by the order of Sultan Mahmud II, is 230 meters long. It was built to separate the palace from the main road.
The tunnel was used to connect Uskudar to Beylerbeyi district until the 1970s. It is a historical tunnel passing between Cengelkoy and Beylerbeyi. It was opened in 1832. The tunnel provides a one-way service from Beylerbeyi to Uskudar.
Thanks to this tunnel, the coastal journey between Uskudar - Beylerbeyi - Cengelköy has been reduced to 15 minutes. The tunnel only allows the passage of small vehicles, not vehicles such as buses and trucks.