In short
- Day one, no ARC: buy a prepaid SIM/eSIM with your passport (airport counters or online) so you have data immediately.
- After your ARC: switch to a postpaid plan — this gives you a real 010 number that works for banking and app verification.
- Settled & saving: move to an MVNO (알뜰폰) for 50–70% cheaper bills on the same network.
- Postpaid needs: ARC + a Korean bank account (for autopay) + your name matching everywhere.
A Korean number isn't just for calls — it's infrastructure. Your bank OTP, the PASS identity app, Kakao/Naver/Toss, and government notifications all need an active number registered in your own name. The catch: a prepaid line opened on your passport gives you data and a number, but usually won't pass Korean identity verification (본인인증). For that you need a postpaid line tied to your ARC.
The path most foreigners take
Arrival — prepaid on your passport
Buy a prepaid SIM or eSIM with just your passport. eSIMs can be bought online before you fly and activate the moment you land; airport counters (Incheon T1 & T2) sell prepaid SIMs too. This covers maps, messaging and translation from day one.
After your ARC — switch to postpaid
Once your physical ARC and a Korean bank account are ready (usually 2–4 weeks after your immigration visit), go to a carrier store and sign up for a postpaid plan (후불요금제). This issues a proper 010 number and turns on banking OTP and PASS. Bring ARC + passport + bank account details, and ask to keep your existing number (번호이동).
Settled — move to an MVNO to save
After a few months, switch to an MVNO (알뜰폰) on the same network for much cheaper bills. Your 010 number transfers. Check the government comparison site mvnohub.kr for current plans. Note: most MVNO sign-up flows are Korean-only.
Prepaid vs postpaid
| Prepaid (선불) | Postpaid (후불) | |
|---|---|---|
| To sign up | Passport only | ARC + Korean bank account (name must match) |
| Identity verification (본인인증) | Usually no — even with a working number | Yes — banking, PASS, gov apps work |
| Contract | None; expires when you stop topping up | Often 12 months |
| Rough cost | ~₩30,000–40,000/mo | ~₩20,000–28,000/mo (MVNO much less) |
| Best for | Day-one data, short stays, waiting on ARC | Residents who need banking & apps |
The name-matching trap
When you register, type your name exactly as printed on your ARC — same order, same hyphens, all caps. If your ARC says KIM JONG-HUN, enter KIM JONG-HUN, not "Kim Jong Hun" or "KIMJONGHUN". A mismatch between your ARC, phone line and bank account is the top reason the PASS app and banking OTP fail for foreigners. The PASS app still handles hyphens and apostrophes in foreign names imperfectly, so if it keeps failing, that's usually why.
The three carriers
Korea has three network owners — SKT (largest coverage), KT (strong urban + rural, foreigner-friendly), and LG U+ (often cheaper urban plans). All MVNOs resell one of these three networks, so coverage is the same — you're really choosing on price and English support. The 010 prefix is universal, so you can't tell a carrier from the number.
Common questions
Can I use my foreign phone?
Usually yes — modern iPhones, Galaxy and Pixel phones support Korean 4G/5G bands. It just needs to be unlocked (not tied to your home carrier). Then insert a Korean SIM or activate an eSIM.
Why does my bank OTP keep failing?
Three things must line up: a postpaid plan registered to your ARC, the name matching your bank account exactly, and a working PASS app. A prepaid passport line or a name mismatch will break it.
Can I keep my Korean number after I leave?
Yes, with planning. Switch to a cheap prepaid MVNO at minimum top-up (~₩5,000–10,000/mo) before leaving — this keeps the number alive for KakaoTalk, banking 2FA and Coupang. Numbers are recycled after about 60–90 days of inactivity.
Do I need an address for postpaid?
Often yes — carriers print a registered address on the contract and won't accept a hotel or guesthouse. Your dorm, employer apartment, or homestay address works.
Sources: Telecommunications Business Act (real-name verification, 전기통신사업법 §50), KCC, carrier foreigner-service pages, and current SIM/MVNO guidance. Government MVNO comparison: mvnohub.kr.
Last verified: July 2026. Prices, data caps and requirements change often — verify on the carrier's site before buying. General information, not legal advice.
Phone or verification trouble?
PASS and OTP issues are common — ask people who've solved them. Post in the community and tag it Living.