Trial runs on Line 1 (now a 29.5 km north-south route) started in March 1999. After six years of construction it opened for regular service on 6 October 1999 as the fourth subway system in South Korea after Seoul, Busan and Daegu. A trip along the line from Gyeyang in the north to Int'l Business District in the south takes approximately 57 minutes.
By October 2012 the line will also connect with the Seoul Subway's Line 7; currently under construction. Incheon Line 1 will get one more station to Songdo Landmark City 0.84 km beyond International Business District Station. Construction is planned to start in 2013 and be completed by the end of 2018.
Incheon's subway is totally underground except for a ground-level section north of Bakcheon.