Phone: prepaid first, postpaid after registration
Before your residence card arrives, many people use a prepaid SIM with their passport (you charge credit in advance). After you get the card, you can sign up for a postpaid plan at a carrier store. Always check the contract length, cancellation fees and add-on services, and do not sign anything you do not understand.
A Korean phone number is used for banking, deliveries and verification texts, so it is best to get one early.
Opening a bank account
You usually need your passport, residence card and a Korean phone number. Some banks also ask for proof of employment or a document confirming a salary account. You may start with an account that has a daily transfer limit, which can be raised later with a transaction history or extra documents.
Be careful about this
If you lend or sell your bankbook, debit card, password or verification codes, they can be used for crimes such as voice phishing, and you can be punished too. Refuse requests to hand over your account when you leave Korea. If a caller claiming to be a bank, the police or prosecutors tells you to move money, hang up and check first.