|Quoting N757KW (Reply 4):|
You would only clear customs if you enter Korea. ICN is not too hard to transfer at. All you do is reclear security, and if you already have a boarding pass you can go directly to the gate. If you do not have a boarding pass for the KUL flight you will need to check in at the transfer desk, after security. Sometimes the transfer desk is open before security. But, I have seen that hit or miss.
|Quoting MRA (Reply 7):|
Jumbo Jet - Unless you are planning to stay overnight in Seoul, leaving the airport to take a quick lunch in Seoul may not really be an attractive option. The one major drawback to ICN is that it is far from downtown Seoul with no rail link: you will either have to take a bus or a taxi, both of which will take about an hour (at least) to get into the city center - much more if you arrive during a particularly heavy traffic period.
That being said, I suggest taking an extra day (or three) to enjoy Seoul in a more relaxed setting!