Qingdao Metro Line 1, the deepest sea-crossing subway in China, opened to traffic on December 30, 2021. It is also the first cross-sea subway line in Shandong province.

With a total length of 60 kilometers, the subway line has 41 stations. The north section has been put into operation in December 2020. The completion of the south section connects the five districts of West Coast New Area, Shinan, Shibei, Licang and Chengyang via key transport hubs including Qingdao Railway Station, Qingdaobei Railway Station and Qingdaobei Bus Station.

The sea-crossing tunnel of Qingdao Metro Line 1 is 8.1 kilometers long including 3.49-kilometer section that goes through the mouth of Jiaozhou Bay. With a maximum depth of 88 meters，it is the first and deepest subway subsea tunnel in China. It takes only 6 minutes to cross Jiaozhou Bay by subway.

After Jiaozhou Bay Bridge and Jiaozhou Bay Highway Tunnel, Qingdao Metro Line 1 has become another cross-sea channel connecting the West Coast New Area and the main urban area of Qingdao.