The rate offered by banks in Korea is better. The KRW exchange rate offered by money changers in Malaysia is around KRW1,000 = RM2.86-RM2.88. However, banks in Korea can offer you around KRW1,000 = RM2.76-RM2.83. Getting KRW1,000 at just RM2.76 is possible at all Hana Bank branches in Seoul (their money exchange booths at the airport quote slightly higher rate) provided you have an Asiana Airlines boarding pass. Otherwise, the rate is KRW1,000 = RM2.83 and this is still better than the rate offered by local money changers. And yes, Hana Bank accepts MYR in all of their money exchange booths as well as in all their 650 branches in South Korea.