Two of Gimpo Airport’s domestic routes are very different trips. Jeju has no train at all, so the only question is what the ticket costs once a suitcase is added to it. Busan has the KTX as the alternative, so the real question is whether flying is worth it at all. This guide covers only Gimpo–Jeju and Gimpo–Gimhae, Busan’s airport — not Gimhae–Jeju, and not flights arriving from abroad.
Jeju: what the ticket actually costs
Jeju Air and Trinity Airways (more on that name below) each publish a weekday tariff for Gimpo–Jeju that shows how the total is built. As read on 27 September 2026, both cover Monday to Thursday:
| Carrier | Fare | Airport charge | Fuel surcharge | Published total |
|---|---|---|---|---|
| Jeju Air, discount fares (할인운임), Monday–Thursday | ₩70,000 | ₩4,000 | ₩20,900 | ₩94,900 |
| Trinity Airways, regular fare, weekday (주중, Monday–Thursday) | ₩70,000 | ₩4,000 | ₩19,800 | ₩93,800 |
Jeju Air’s page says its fuel surcharge is the amount that applies to tickets issued from 1 September. Trinity’s table states no ticketing period for its surcharge, which is lower than Jeju Air’s. Treat these totals as published reference tariffs, not as the price you will pay: Jeju Air’s fare page says fares can vary with the time of purchase, so the total your own booking screen shows for your date is the one to compare. Jeju Air’s table also lists a flexible-surcharge tariff (탄력 할증 운임) for the same route that totals ₩131,400, so the day you fly can change the tariff you are quoted.
Korean Air, Asiana, Jin Air, Air Busan, Eastar Jet, Air Seoul and Parata Air also fly the route on the Wednesday 30 September 2026 timetable, and this guide gives no fare for them.
The bag is where the comparison gets tricky, so line up the free allowance before you line up the fares. Jeju Air’s STANDARD fare carries 15 kg of checked baggage, and Asiana’s domestic allowance is 20 kg per person. As read on 26 September 2026, Jeju Air’s baggage page gives ₩10,000 per extra 5 kg bought online in advance and ₩3,000 per extra kg at the airport or a branch, on top of the 15 kg its STANDARD fare carries — so the same extra 5 kg costs more at the airport than bought online in advance.
Trinity publishes something narrower, and only for a different case. Its page states a gate-check charge — ₩10,000 per bag, plus ₩3,000 per kg of excess weight — for a carry-on that exceeds the cabin allowance and has to be checked at the gate; it is not a price for a suitcase you check in. What Trinity charges for checked weight beyond the free allowance, including weight bought in advance, is available only through its baggage calculator.
Busan: adding up the flight door to door
Flying to Busan lands at Gimhae, 17.1 km from Busan Station by the Busan Transportation Corporation’s route search. The KTX side is priced and timed in KTX vs express bus, from readings dated 4 September 2026. Before comparing them, here is what each leg of the flight actually publishes.
| Leg | What’s published |
|---|---|
| Seoul Station → Gimpo | About 22 minutes and ₩1,750 by transit card on AREX’s All-Stop train, from the Seoul Transportation Corporation’s route search, which prints its fares as reference figures. The walk from the station to the domestic terminal isn’t published on the operator pages checked |
| Time needed at Gimpo | Trinity closes check-in 30 minutes before departure, and Jeju Air’s mobile check-in runs until 30 minutes before. Arrival advice differs: Trinity recommends 50 minutes before departure, and Jeju Air’s steps run from 1h30m to 30 minutes before with security 50 minutes before. Asiana’s check-in page says at least one hour and its counter page says at least two |
| The flight | A 1h 05m scheduled block on most departures. Korean Air, Air Busan, Trinity and Jeju Air fly it on 30 September; this guide gives no Busan airfare, so read yours on the airline’s own booking screen for your date |
| Gimhae → Busan Station | 38 minutes 29 seconds and ₩1,800 by card (₩3,600 cash), from the Busan Transportation Corporation’s route search: light rail to Sasang, Line 2 to Seomyeon, then Line 1 to Busan Station. The time to get out of Gimhae’s terminal isn’t published on the operator pages checked |
Add the published legs for a flight on Trinity’s 50-minute arrival advice and the trip from Seoul Station to Busan Station comes to about 2h55m: about 22 minutes to Gimpo, 50 minutes ahead of departure, the 1h05m flight and 38 minutes 29 seconds from Gimhae. For money, the two ground legs cost ₩1,750 and ₩1,800 by card, and the airfare comes on top. The 22 minutes is the “about” figure the Seoul route search prints, while the Busan search prints an exact 38 minutes 29 seconds. The total leaves out the two walks that none of the operator pages checked publishes: from Gimpo Airport station to the domestic terminal, and out of Gimhae’s terminal.
Two things to know about the ground legs. The airport’s own list for Gimhae is 15 bus routes and a taxi table of 5 destinations, and none of them ends at Busan Station; the rail route above is the one that reaches it. And Asiana’s two pages disagree on when to arrive — at least one hour on its check-in page, at least two on its counter page — so plan on the longer one if you fly Asiana’s codeshare. Korea’s rail and bus fares for this corridor were checked separately, on 4 September 2026 — see KTX vs express bus — and that guide’s KTX journey time is what this total has to be set against.
On Wednesday 30 September 2026, 17 flights are scheduled from Gimpo to Gimhae — Korean Air’s first at 07:00, Air Busan’s last at 20:00 — but that’s a single day’s count on a schedule that runs only through 24 October 2026, not a year-round frequency. Jeju’s own service is a different shape entirely: more than a hundred departures on that same Wednesday, roughly every five to fifteen minutes from 06:00 to 20:45, dense enough that timing rarely matters on that route.
Getting through Gimpo
Gimpo’s own domestic-departure pages disagree on where the ID check actually happens. The Korean page places it at the entrance to the departure area, before security, with a guard checking your face against your ID — hat, mask and sunglasses off. The English page instead describes the check happening at the boarding gate. Plan for the earlier, stricter version and have your passport and boarding pass ready before security; that’s the safer reading of the two, and the one an English-speaking visitor doesn’t otherwise see.
Don’t plan on the biometric fast lane either. One of the airport operator’s own pages restricts it to Korean nationals; another lists a passport among the documents accepted at the registration desk. Neither page settles whether a foreign visitor can actually register, so treat the ordinary ID check as the plan rather than the shortcut.
An expired passport or a photocopy can’t be used to board a domestic flight; the Korea Airports Corporation has stated the rule since 2022. And from 20 April 2026, passengers are limited to two power banks each, rated 160Wh or under — charging one, or using it to charge anything else, is banned outright once you’re on board. Gimpo’s Korean page adds that a battery over 100Wh is one to ask the airline about, while its English page says spare batteries of 100–160Wh are “generally” allowed, so ask before you fly.
One carrier mid-rename, two mid-merger
T’way Air’s website now redirects everywhere to Trinity Airways — same operator, new name on every page, including the fare table quoted above. If you booked as T’way, or you’re searching for it, look for Trinity instead.
Korean Air and Asiana are due to merge into one integrated carrier on 17 December 2026. As read on 27 September 2026, Asiana’s site links an integration FAQ (“통합 관련 자주 묻는 질문”) from its header and footer, and that FAQ opens with 17 December 2026 as the day the two airlines become one. A booking made now is a booking with the airline shown on the page — but if your travel date sits close to or past the merger date, confirm which brand’s baggage and change rules actually apply before relying on anything above.
Liquids, and what still isn’t published
Korea’s aviation-security portal, Aviation Security 365, lists liquids, aerosols and gels among the items banned in the cabin and limits that item to international flights: the Korean edition reads “국제선에 한함”, and the English edition reads “(For International flight)”. The liquids restriction is therefore listed for international flights only, and is not listed for domestic ones. For anything else you’re unsure about packing, the portal’s cabin list is where to check.
What the operator pages checked still don’t publish: the walk from Gimpo Airport station to the domestic terminal, the time to get out of Gimhae’s terminal, and what Trinity charges for weight bought in advance. If your fare’s free allowance is tight, get that figure from the airline’s own booking flow before you fly rather than from an estimate here.
What to actually book
For Jeju, compare the all-in total your own booking screen shows for your date, with the bag you will actually check, not the headline fare. As read on 27 September 2026, the published Monday–Thursday tariffs total ₩94,900 at Jeju Air and ₩93,800 at Trinity, but Jeju Air’s page says fares can vary with the time of purchase and its flexible-surcharge tariff totals ₩131,400. If you’re adding a full 5 kg on Jeju Air, buy it online in advance rather than at the airport, and get Trinity’s checked-bag price from its calculator before you count on a total. For Busan, book the flight if the KTX doesn’t suit your schedule or your route into Seoul Station is awkward, but set the total above — about 2h55m from Seoul Station to Busan Station on Trinity’s arrival advice, before two walks that none of the operator pages checked publishes — against the KTX journey time before you assume the flight saves time.