The map looks like one system. The fares are not.
Most of the network charges one distance-based fare and lets you transfer for free. A few lines sit on the same map, take the same card, and charge extra. Nothing tells you which is which until the money is gone.
Line 2 goes both ways round
Line 2 is a loop, so it has no final destination to point at. Instead the signs say 내선순환 (naeseon-sunhwan) and 외선순환 (oeseon-sunhwan).
내선순환 (naeseon-sunhwan) is the inner track. It runs clockwise, and station numbers go up.
외선순환 (oeseon-sunhwan) is the outer track. It runs anticlockwise, and station numbers go down.
If you cannot remember which is which, use the numbers on the platform sign. Going from Hongik University (239) to Gangnam (222), the numbers need to fall, so you want 외선순환 (oeseon-sunhwan).
Boarding the wrong one is not a disaster. It is a circle. You will get there, having seen more of Seoul than you planned.
Express trains cost the same
Some lines run 급행 (geuphaeng, express) alongside 일반 (ilban, local). Line 9 is the one most visitors meet, and end to end the express saves about twenty minutes.
Two things to know. The fare is identical, so there is no reason to avoid the express. And it skips stations, so the only thing that matters is whether it stops where you are going. The platform displays list the stops for the next train; if your station is not on that list, wait for the local.
The lines that charge extra
Two lines look like ordinary subway on the map and are not.
신분당선 (Shinbundang Line) runs south from Sinsa through Gangnam to Gwanggyo. It is fast, and it adds its own charge on top of the normal fare:
| Section | Added |
|---|---|
| Sinsa to Gangnam | 700 won |
| Gangnam to Jeongja | 1,000 won |
| Jeongja to Gwanggyo | 1,000 won |
So Sinsa to Gangnam costs 2,250 won rather than 1,550. It is also not covered by the 기후동행카드 (gihu-donghaeng-kadeu, Climate Card), which catches people who bought the pass expecting it to cover everything inside Seoul.
GTX-A is a different thing again: an express line built for commuters from outside the city, running far faster and far deeper underground. Its fare starts at 3,200 won on weekdays and 2,850 won at weekends, plus 250 won per 5 km. Dongtan to Suseo, about 33 km, costs 4,450 won. The Seoul Station to Suseo section opened in June 2026.
Neither is a trap exactly. Both are worth the money when you need the speed. You just want to know before you tap, not after.
The 15-minute rule
You go through the gate, then realise you need the toilet, or you got off one stop early, or you took the wrong exit and the right one is on the other side.
Tap back in at the same station within 15 minutes and the fare is not charged again.
The conditions are simple:
- The same station you left, not a nearby one
- Within 15 minutes
- With a transit card, not a single-journey ticket
- Once per journey
It has covered Seoul Metro lines since 2023, and since June 2026 it covers Korail lines too — the Gyeongui-Jungang, Suin-Bundang, Gyeongchun, Gyeonggang and Seohae lines.
It does not apply on the Shinbundang Line, Incheon Metro or the airport express. GTX-A has its own version with a 10-minute window instead of 15.
SRT is becoming KTX
For intercity travel there were two high-speed operators, KTX and SRT, with separate tickets and separate apps. That ends this week.
SRT ran its last train on 31 August 2026. From 1 September the service is KTX, run by Korail, and the SRT brand is gone. Suseo station keeps its trains and gains connections it did not have before. Booking is now one app, Korail+, for departures from both Seoul and Suseo.
Fares came down about 10% to match the old SRT level, so if you compared prices before, compare again.
None of this affects a normal day of sightseeing on lines 1 to 9. It matters when you head for Gangnam on the fast line, when you take a train from Suseo, or when you walk back through a gate you just walked out of.
