Seoul Subway Line 7

Seoul Subway Line 7 of the Seoul Metropolitan Subway was built from 1990 to 1996 (Jangam-Konkuk Univ.) and was completed on August 1, 2000 (central section 17 km (11 mi). Konkuk University to Sinpung); the western section between Sinpung and Onsu was put into service on February 29, 2000. This north-south line does not run through the city centre but links Gangnam directly to the northeastern districts of Seoul. In 2019, Line 7 had an annual ridership of 380 million or 1.04 million passengers per day. Although most trains run between Jangam and Seongnam, some trains short turn at Onsu station and some trains start at Dobongsan station.

Line 7 uses a dark yellow-green triangle shape for its station sign design, which it shares with Lines 5 and 8. The upper half of the triangle contains the station number, with the English and Hanja names of the station displayed in the bottom half. The middle of the triangle displays the Hangul name of the station. The triangle is pointed in the direction that trains run; an arm jutting out of the apex displays the next station, while another arm projects out of the straight side in the back, pointing to the previous station. This design is similar to the design used in Line 6, but with a triangle instead of a chevron.

All trains on Line 7 are monitored by 1,008 closed-circuit television cameras that were installed in June 2012.

The extension to Incheon Subway Line 1 was designed to relieve the traffic congestion in western Seoul and northern Incheon. Nine stations were added on October 27, 2012, for the 10.2 km (6.3 mi) extension, starting from Onsu Station of Line 7 and ending at Bupyeong-gu Office Station of Incheon Subway Line 1.

Line 7 was extended west of Bupyeong-gu Office. Construction on the two-station, 3.94 km (2.45 mi) extension to Seongnam began in 2013 and was completed on May 22, 2021. The extension allows for transfers to Incheon Subway Line 2.