Let me introduce you to bus number 6015, which is convenient to get to Incheon Airport.

Riding time: 1 hour~
In front of Exit 8 of Myeongdong Station
Fee: KRW 16,000 for adults
12,000 won for children (cash only)
The first bus leaves at 5:15 and last bus leaves at 19:00

(Bus timetable 5:15 6:45 10:00 11:30 14:30 16:10 19:10)