A friend of mine at my hostel here in Seoul needs to get to Gimpo Airport in the morning and is asking what time the subway system commences operation.
I've looked at the Wikitravel page for Seoul and the Wikipedia page for the Seoul Metro, but this information is proving a little difficult to find.
This is what it says on the official Seoul tourist site:
Trains run non-stop from approximately 5:30 am until midnight.
The official Seoul Metro site has train times and states they start operating at 5:35 and finish at 00.45.
While the operation starts from 05:30 to 24:00 approximately, the actual timetable differs among different stations. You can check out each station's timetable at the official subway website, for example in the case of Dongdaemun.
On weekday, First train starts 05:19 (down) or 05:31 (up), and Last train starts 24:49 (down) or 24:58 (up).
Not sure about the morning, but if you catch a subway past 24:00 it will probably stop soon. I've rode on a subway until 00:30 after midnight until it came to its last stop, which was one stop away from where I needed to be.
