How do I open a bank account in Korea as a foreigner?

You can often keep a Korean bank account after leaving, but it gets harder once your ARC expires, since banks tie accounts to your residency status and many now restrict or dormant-flag accounts of non-residents to prevent misuse. Before you go, tell your bank your plan and ask what they allow, set up internet banking and a certificate (geumyung certificate) while you still can, and keep the account active with small periodic transactions so it isn't frozen for inactivity. Foreigner-friendly banks like Hana and Shinhan are worth asking directly. Note that some services require a valid Korean phone number and ID for verification, so keeping a number active (or an MVNO) helps you actually use the account from abroad.