You can get to COEX easily using the subway.
Select your origin and it will tell you how to get to COEX.

From Gangnam Express Bus Terminal      From Nambu Terminal
From East Seoul Bus Terminal    From Gangbuk (center of Seoul) area

From Gangbuk (center of Seoul) area
Take the Subway Line #2 at Euljiro or City Hall station in the direction towards Gyodae
(Seoul National University of Education), and alight at Samsung station. Use the Exit No. 5 or 6 connected to the COEX Mall.

- Transfer to the Subway Line #2 towards Jamshil from Line #4 at Sadang station, and get off
at Samsung station. Use the Exit No. 5 or 6 connected to the COEX Mall.
- Accessible within one hours from any part of Seoul: Can be reached within one hour from
any part of Seoul through well-developed road network and subway lines #2 and
#9(scheduled).