Circular line (New Taipei)

The Circular or Yellow line (code Y) is a metro line in New Taipei City. The first phase of the project consists of the section from to  and is approximately 15.4 km long with 14 stations. This initial section was opened on 31 January 2020. Hitachi Rail Italy supplied 17 sets of 4-car driverless medium-capacity trains for the line.

Construction
Hitachi Rail STS supplied electromechanical equipment for the line, including driverless technology and CBTC signaling. , currently the only underground station on the line, was constructed by RSEA Engineering Corporation and employed the cut-and-cover method.

Construction for the first phase officially broke ground on 11 July 2011 on a 6.3 km elevated section between Zhonghe and Banqiao. The section is estimated to cost NT$13.7 billion, with the entire first-stage 15.4 km route estimated to cost NT$54.7 billion to construct.

The line includes the first elevated split platforms in the system at, , and due to the narrowness of the available station area.

Stations in operation
The western section of the line officially opened on 31 January 2020.

After 3 April 2024, services between Zhonghe and Banqiao were temporarily suspended due to the 2024 Hualien earthquake. The repair work will take 1 year to complete.

Stations under construction
The north and south sections are approved for construction. Currently under construction, with estimated completion in 2029.

South section
Stations Y01–06 are approved for construction. (Unopened stations' names are to be confirmed)

North section
Stations Y21–32 are approved for construction. (Unopened stations' names are to be confirmed)

Planned stations
The east section is still under planning and subject to change. After this section is complete, the Circular line will go in a circle.

East section
(Unopened stations' names are to be confirmed)