Originally Posted by
MSPeconomist
There are regular and "luxury" airport buses that serve many of the major hotels, CODEX, and the main train station IIRC. With luggage, this can be much more convenient than using the train/subway.
There's also a new monorail that goes around in a loop covering the area around the airport.
Yes, when I was in Seoul, I stayed at a guest house near the main train station. My landlady recommended going to ICN on the bus that left from the bus plaza outside the station. It was fast and efficient, running on a dedicated busway for much of its length, and reasonably priced, and I enjoyed seeing a bit more of Seoul.