Blue, green, red, yellow: how to read a Seoul city bus before you board

Three buses pull into the same stop on Jongno at once, nose to tail, and none of them will wait long. One is blue, one is green, one is red, and the digital sign on the pole is already counting down the next arrivals in minutes. The subway teaches you to read a map; the bus asks you to read a colour, a number, and the driver's willingness to stop, all in the four seconds before the doors close.

The colour is the route type

Seoul paints its buses by function, and once you know the code you can triage a stop at a glance. A blue bus (파란 버스, paran beoseu) runs a trunk line, long and mostly straight across the city; a green bus (지선 버스, jiseon beoseu) is a feeder, looping through neighbourhoods and connecting you to the nearest subway. Red buses (광역버스, gwangyeok beoseu) are wide-area expresses that leave Seoul entirely for Gyeonggi towns like Suwon or Yongin, and yellow buses (순환버스, sunhwan beoseu) are short circulators inside the downtown core.

The number carries information too. A four-digit blue or green route encodes its start and end districts, so a bus labelled 7016 begins in zone 7 and works toward zone 0, the old city centre. You do not need to decode it to ride, but it explains why two buses with almost identical numbers head in the same broad direction.

Flag it, then tap on

A Seoul driver will not always stop for a bus stop. If no one is waiting visibly at the pole and no one on board has pressed the bell, the bus may sail past, so put your arm out as it approaches, the way locals do. Board through the front doors only, and tap your card flat on the reader beside the driver; you will hear a chime and see the fare deducted on a small screen.

A card tap on a blue or green bus runs about 1,500 won, a red wide-area bus closer to 3,000, and paying by card is not merely convenient. Cash fares are higher, drivers no longer carry much change, and cash forfeits the transfer benefit entirely. Buy a T-money card (티머니) at any convenience store for 2,500 to 4,000 won and load it at the counter or a subway machine.

The tap you cannot skip

Here is the move that separates a smooth rider from a confused one: you tap again when you get off, on the reader by the middle doors. This second tap is the 하차 태그 (hacha taegeu), the alighting tag, and it is not ceremonial. The system charges by distance on longer routes, and if you forget to tap out, it assumes you rode to the end of the line and bills you the maximum fare on your next boarding.

Tapping out is also what unlocks the transfer (환승, hwanseung). Tap off one bus and onto another, or onto the subway, within 30 minutes and the second ride is free or nearly so, up to four transfers across a single journey. After 21:00 the window stretches to 60 minutes. Skip the tap-out and the system sees a fresh full-fare trip, not a transfer, every time.

내릴 때도 카드를 한 번 더 찍어야 환승이 됩니다.

Finding your stop in a moving window

Every stop is announced in Korean and English over the speakers, with an LED strip above the aisle showing the current and next stop; larger routes add Chinese and Japanese. When your stop is next, press one of the red bell buttons (벨, bel) mounted on the poles and handrails, and a light confirms the driver has seen it. Press it once, early, rather than lunging as the bus brakes.

Do not trust guesswork for which bus to take. Naver Map and KakaoMap both show live bus positions, telling you a given route is four minutes and two stops away, and the pole at every stop carries a five-digit stop number (정류소 번호) you can type into either app to pull up real-time arrivals for that exact spot.

What it costs, when it runs, one thing not to do

Buses run from roughly 04:30 to just past midnight, after which the night network takes over. The owl buses (올빼미버스, olppaemi beoseu), route numbers prefixed with N, cover the main corridors between about 23:30 and 05:00 for around 2,500 won a ride, and on a Friday night the N26 or N16 fills with people the last subway left behind. Rush hour, roughly 07:30 to 09:00 and 18:00 to 19:30, packs the trunk buses solid; a feeder green bus is often the quieter way to reach the same subway line.

The one mistake to avoid is treating the bus like the subway, where a single tap in and a walk out is enough. On the bus, forgetting the exit tap does two things at once: it can overcharge you on distance-based routes, and it silently kills the transfer you were counting on. Tap on at the front, tap off at the middle doors, and the whole network behaves.