. Line 9 will run east from Gimpo Airport along the south bank of the Han River. Construction of the first phase began in April 2002 and is due for completion in 2008.
. New Bundang Line will be a new line from Gangnam in Seoul to Jeongja in Bundang, Seongnam. Construction is due to be completed in 2010.
Several existing lines are also currently undergoing extension:
. Line 3 will be extended south from Suseo to Garak Market and Ogeum, interchanging with lines 8 and 5 respectively, by 2009.
. By 2008, the Bundang line will be extended north from Seolleung to Wangsimni and south to Yongin and Suwon, with eventual plans for it to run all the way to Incheon, completing a southern outer semicircle.
. Line 7 will be extended west by 6.1 miles (9.8km) from Onsu to meet Incheon Subway line 1 at Bupyeong-gu Office. Nine new stations will be added by 2010.
There are several major works still in the planning stage:
. A 6.25 mile (10km) extension to the New Bundang Line (see above) northward from Gangnam station to Yongsan is under consideration. If approved, the project is estimated to cost at least 400 billion won.
. By the end of 2011, Seoul City plans to build a 6.7 mile (10.72km) 'light' subway line from Ui-dong to Sinseol-dong in northern Seoul. The line is expected to carry 110,000 passengers a day and will have 12 stations. It will connect to Line 4 at Sungshin Women's University Station, Line 6 at Bomun Station and Sinseol-dong Station (Line 1 & 2).
. EverLine Rapid Transit System will be a new line branching off the Bundang line extension and running east into Yongin and then to the theme park Everland.
. An extension of the Jungang Line from Deokso is also planned. This should eventually terminate in Yongmun Station.
