Getting a phone: the number matters more than the plan
ENEnglishA Korean phone number is not just a way to make calls. It is the key that unlocks most
of the country's online life, and the wrong kind of number will quietly lock you out of
things you need.
That is the part worth understanding before you compare prices.
WHY THE NUMBER IS THE REAL ISSUE
Korean websites and apps constantly ask you to prove who you are. This is called
본인인증 (identity verification), and it usually works by matching your name, date of
birth, and your phone number against the records the carrier holds.
You will hit this when you try to:
- Use internet banking, or open an account with an app-only bank
- Log into government services
- Buy train or concert tickets
- Order delivery, use secondhand marketplaces, book a hospital appointment
Here is the catch. Verification generally needs your number to be registered against
your 외국인등록번호 — the number on your ARC. A line opened on a passport alone often
cannot pass it.
So a cheap tourist SIM will let you call and use data, and still leave you unable to do
half the things you actually got the phone for.
TWO ROUTES, AND WHEN EACH ONE MAKES SENSE
1. Prepaid (선불), with your passport
You can usually get this on day one, before your ARC exists. It is the right answer
for your first weeks, and it solves the chicken-and-egg problem where a bank wants a
phone number and a phone shop wants a bank account.
Two things to check before you pay:
- Many passport-only prepaid lines are set to terminate automatically around 90 days
after activation. If nobody mentions this, ask. Losing the number later is a real
problem, because it may already be tied to accounts you created.
- Confirm whether the line can pass 본인인증. Often it cannot, and that is the main
limitation, not the price.
2. Postpaid (후불), with your ARC
Once you have your ARC, you can sign up much like a Korean resident, with monthly
billing and a number that works for identity verification.
If you already have a prepaid number, ask about keeping it (번호이동) rather than
starting fresh. Changing your number after months of registering it with banks,
delivery apps, and your employer is more painful than it sounds.
알뜰폰: THE SAME NETWORK FOR MUCH LESS
알뜰폰 (MVNO) providers rent capacity from the three major carriers and resell it.
Your calls and data travel over the same towers. Coverage and speed are essentially the
same — you are not buying a worse network, you are skipping the retail markup.
The difference is service, not signal: fewer physical shops, less hand-holding, and
support that may be Korean-only.
Combine it with a 자급제 phone — one bought unlocked, from a shop or online, rather
than bundled with a contract — and you get the cheapest arrangement available:
자급제 handset + 알뜰폰 SIM = no lock-in, low monthly bill, keep the phone
This is what many Koreans do too, and it is usually the recommendation for anyone
staying more than a few months.
CONTRACT TRAPS TO WATCH FOR
- A "free phone" is a loan. The handset cost is spread across your monthly bill for
24 months. Leaving Korea early does not cancel it.
- Your contract may be limited to your visa's remaining validity. Check what happens
at renewal, and keep your carrier updated when you extend your stay.
- Watch for bundled add-ons signed up at the counter — insurance, subscription
services, extra data packs — with a free first month and automatic charges after.
Ask directly: "이 요금제에 추가된 것 있나요?" (Are there add-ons on this plan?)
- Read the total monthly figure, not the headline plan price.
If a deal is explained to you in a language you are not comfortable in, it is fair to
ask for the terms in writing and take them home before signing. A shop that will not do
that is telling you something.
WHEN YOU LEAVE KOREA
Cancel properly, in person or through the carrier's process. A line left running keeps
billing, and unpaid telecom debt can follow you back if you return.
Do this before your last week, not on your way to the airport. And unwind anything that
depends on the number first — bank verification, delivery apps, two-factor logins —
because once the number is gone, recovering those accounts is genuinely difficult.
WHERE TO CHECK
Plain-language legal guide (Korean): https://easylaw.go.kr
Government services portal: https://www.gov.kr
Immigration (ARC): https://www.hikorea.go.kr
Plans and promotions change constantly, and every provider has different rules about
foreign customers. Compare the current offers rather than trusting any list, including
this one.
Written by the Go Korea team, accurate to the best of our knowledge as of August 2026.
Terms differ by provider and change often — confirm the details with the provider before
signing anything. This is general information, not advice about a specific contract.
If a provider told you something different, please reply and tell us. Rules around
foreign customers vary more between shops than they should, and hearing what actually
happened to you helps the next person.