東區海底隧道
The western terminus of the line is North Point, providing cross-platform interchange together with the neighbouring station of Quarry Bay. East of Quarry Bay, the line passes under Victoria Harbour to Yau Tong station, a station serving the East Kowloon neighbourhood of the same name, using the rail tunnel of the Eastern Harbour Crossing. From Yau Tong, the line passes through the Black Hill Tunnels to enter Tseung Kwan O New Town at Tiu Keng Leng.