I want to confirm what geosch found. I have attached the photo of an ATM which I was able to get money fee-free. (I believe my card is in the Cirrus network). It is located in the end of the the J aisle. It is quite convenient as J is close to the escalator near the 1/F exit of immigration / custom.
(Be aware of an ATM operated by KEB on the same Departure Floor, it also want 4000 won in fees. Even offered to deduct my account in US$ with a very bad exchange rate.)
The ATMs are starts in Korean. But once you put your card in, you can choose "International". There you can choose many difference languages. There is also an ATM that seems to only offer to take money from credit card, I didn't understand it so I passed.
Last edited by kash; Jan 6, 2016 at 2:45 pm