Use COEX as the exact anchor
COEX, Samseong Station and Bongeunsa Station are more precise than the broad label Gangnam. Search the current airport transport information for a practical stop and compare the walk to the exact hotel or venue entrance.
Rail is a connected journey
An airport railway route reaches the Seoul network but not COEX directly. Add the transfer, platform movement and final walk. Rail can still be economical for a traveller with light luggage, but its first segment should not be compared with a door-to-door bus or taxi total.
A group can change the commercial winner
Bus fares multiply per traveller while a suitable taxi or private transfer is shared, subject to vehicle and luggage capacity. Enter the group and bag count in the finder, then check a live bookable option only after the door-to-door comparison is clear.