To send mail, visit a post office or put your mail in a red street mailbox. For non-standard size mail or international mail, you must visit the post office.
Customers can write Korean addressees in English, although writing in Korean can result in faster delivery and fewer problems. All letters and packages must have the recipient's postal code (Each post office has a book listing every postal code for the country. Customers can look up postal codes online as well).
< Right Locaton for Postal Codes >
Customers sending packages overseas will have to fill out a customs declaration form. Post offices are open 9:00a.m.~6:00p.m. (until 5:00p.m from Nov.~Feb.).
Banking services are only available until 4:30p.m. Post offices are closed on Saturdays, Sundays and holidays.
Image Source
http://www.koreapost.go.kr/eng/sub/subpage.jsp?contId=e1030100
