The currency of South Korea is the South Korean Won.
In addition to ATM’s and traveller cheques, you can find money changers in Myeongdong that is a popular tourist and shopping district in Seoul. However, money changers can also be found in other areas of Seoul like Dongdaemun, Itaewon and Mapo-Gu. The Keb Hana Bank is a hub for money exchange.