How to Get a Mobile Phone and Choose a Plan

Postpaid and prepaid: the difference

Item	Postpaid	Prepaid
Documents needed	외국인등록증 (or passport)	Passport or 외국인등록증
How you pay	Use for one month, pay the next month	Top up first; service stops when the money runs out
Bank account or card	You usually need a bank account for automatic payment, or a card	Not needed
Identity check (본인인증)	Usually possible	Depends on the company
Price	Better if you use a lot of data	Better if you use a little

In Korea, you often need to verify your identity with your phone (본인인증) to use bank apps, government apps, and delivery apps. So, many people change to a postpaid plan or a plan that allows identity checks after they get their 외국인등록증.

Steps

1. Prepare your documents. Prepare your 외국인등록증 (or passport) and a bank account or debit card in your own name. Some companies ask for a copy of your bankbook or a bank account check.
2. Choose where to sign up. Choose from a store of the 3 big carriers, a 알뜰폰 store, or online.
3. Go yourself. Always sign up in your own name. It is safer not to let someone else open the phone for you.
4. Read the contract. It shows the contract period, the cancellation fee, the phone installment payments, and extra services. If you do not understand a word, ask right there.
5. Get your USIM and activate the phone. After activation, install the carrier's app and check your bill and data use.

Opening a phone online by yourself

Some 알뜰폰 companies run online self-activation pages only for foreigners. You upload a photo of your passport or 외국인등록증 and do a face check. Then they send you a USIM by delivery, and you activate it yourself. Some sites have English guides.

Be careful:

• Always apply on the company's official website.
• Check carefully before using an activation page that you opened from a social media ad or a messenger link.
• Do not give your USIM to another person after activation.

When you have little time left on your stay

• By law, if there are 60 days or less left until your permitted stay ends, you cannot sign up for a regular (postpaid) mobile phone. In this case, you can use a prepaid mobile phone.
• But each carrier has its own stricter rules. Some do not accept postpaid plans if your card has less than 6 or 12 months left. The rules differ by company, so ask the store first. (Official confirmation needed)
• If you cannot get postpaid, you can use a 알뜰폰 no-contract plan or a prepaid plan. A no-contract plan has no fixed contract period, so there is no cancellation fee when you cancel.
• If you extend your stay, you must give your new 외국인등록증 to the carrier to extend your phone service period too. If you do not, your line may be stopped.

How to choose a plan

1. How much data do you need? If you make a lot of video calls and watch many videos, you need a lot of data. If your dormitory or workplace has Wi-Fi, a plan with little data is enough.
2. How much do you call other countries? Some plans let you add an international call discount service. But these days, internet call apps (using Wi-Fi) are often cheaper. Calculate first.
3. Does it have a contract period or not? With a contract period, the price is lower, but you pay a cancellation fee if you cancel early. If you are not sure you will stay in Korea long, a no-contract plan is safer.
4. Are you buying the phone in installments? If you pay for the phone over 24 or 36 months, that amount is added to your monthly bill. The phone service fee and the phone installment payment are different money. Do not mix them up.
5. Is there help in many languages? Check if the customer center can help you in your language. This makes things easier later.

Never do these things

• Opening a phone in your name and giving it to another person (lending your name, 명의대여) — This breaks 전기통신사업법 (Telecommunications Business Act) Article 30. The punishment is up to 1 year in prison or a fine of up to 50,000,000원.
• Opening a phone in another person's name (using someone's name without permission, 명의도용) — This breaks 전기통신사업법 Article 32-4. The punishment is up to 3 years in prison or a fine of up to 100,000,000원.
• Selling a USIM you activated — A phone made this way is called a 대포폰 (illegal phone in someone else's name). These phones are used for voice phishing (phone scam) crimes.
• In fact, in 2025, a court sent a person to prison for 4 years for activating thousands of illegal USIMs and handing them over.
• If the court also finds that you helped a fraud, the punishment is heavier, and you must also pay the victims for their losses. For foreigners, a criminal punishment also causes big problems for your visa status and for coming back to Korea.
• "I will pay you for each USIM" or "Just lend me your name" — these are all offers to commit a crime. Say no and report it to 112.

When you cancel

• If your contract period is not finished, you must pay a cancellation fee (return of discounts). The amount depends on the time left and the discount you received.
• If you still owe money on your phone installments, you must pay it all at once.
• If you do not pay your bills, unpaid charges add up, and you may be refused when you try to sign up again later.
• Always cancel before you leave Korea. If you leave without canceling, the charges continue.
• You can cancel through the customer center, a store, or the carrier's app. It is good to get a cancellation certificate.
• You can also keep your number and move only to another company (number porting, 번호이동).

Frequently asked questions

Q. I do not have my 외국인등록증 yet. A. You can activate a prepaid USIM with your passport. You can buy one at the airport or at a store. When you get your card, you can change to postpaid.

Q. Is the call quality bad on a 알뜰폰? A. 알뜰폰 companies rent the networks of the 3 big carriers as they are. On the same network, the quality is the same. But customer service and extra services may be different.

Q. My company says it will open a phone for me in the company's name. A. The rule is to open a phone in your own name. A phone in the company's name causes problems when you leave the job.

Q. I cannot read my phone bill. A. You can see your usage and bill amount in the carrier's app. If you do not understand, you can get interpretation help at 1345.

Q. There is a charge I do not know about. A. You may be signed up for an extra service. Ask the customer center to cancel it. If it is not solved, you can use 방송통신위원회 (Korea Communications Commission) or the telecom dispute mediation process.

Where to get help

• 외국인종합안내센터 (Immigration Contact Center for foreigners) 1345 (many languages)
• 방송통신위원회 www.kcc.go.kr
• Each carrier's customer center (the number is in your contract)
• Police 112 (if someone uses your name, or offers you money for a 대포폰)