You land at Incheon, turn off airplane mode, and your phone either finds a network or it doesn’t. A week later, if you’re staying, a different problem shows up: your bank app wants to send a code to “a phone number in your name,” the delivery app wants the same, and the prepaid SIM you bought at the airport doesn’t count.
Those are really two separate questions, and most SIM guides blur them. One is “how do I get data today?” The other is “how do I get a Korean number that works as my ID?” The answer depends almost entirely on whether you’re visiting or living here. This is how I explain it to friends who are moving to Seoul.
First, which situation are you in?
- Visiting for days or weeks. You need data, maybe a local number for restaurant bookings or taxi apps. A prepaid SIM, an eSIM, or your home carrier’s roaming will do. Your passport is enough.
- Living here (work, study, family visa). You’ll register as a foreign resident and get an Alien Registration Card (외국인등록증, ARC). Once you have it, get a regular phone plan in your own name. That number becomes how Korean apps and banks recognize you.
If you’re in the second group, you’ll probably be in both situations for a few weeks: anyone staying longer than 90 days has to apply for registration within 90 days of entry, and the card itself usually arrives a few weeks after you apply. A prepaid line covers that gap. Our ARC guide walks through registration itself.
Visiting: prepaid SIM, eSIM, or roaming
Before you choose, check two things on your phone. It must be unlocked, meaning not tied to your home carrier. If you want an eSIM, the model must support it. Many recent flagships do, while some mid-range Android phones don’t.
Then pick one of three:
- Prepaid SIM or eSIM from a Korean carrier. SK Telecom, KT and LG U+ all have counters in the arrival halls at Incheon, some open around the clock. The airport is convenient but rarely the cheapest place. Expect your passport to be checked. A passport alone generally gets you one prepaid line.
- A travel eSIM bought online before you fly. Install it at home or on airport Wi-Fi, since it needs an internet connection to activate. Many of these are data-only, with no Korean phone number, so check before you buy if you’ll need to receive texts.
- Your home carrier’s roaming. It’s the least effort and keeps your own number, but it’s usually the most expensive per gigabyte. Check the daily rate before you rely on it.
For short trips, a data-only eSIM plus your home number for messages is often enough. If you need a Korean number to book things, buy a prepaid plan that includes one.
Living here: why the number has to be in your name
This is the part that catches newcomers. In Korea, many apps and websites confirm who you are through your phone. You enter your name, date of birth and number, and the carrier confirms the line belongs to you. This is called identity verification (본인인증), and the carriers’ PASS app is the most common way to do it. PASS itself states it only works on a phone registered in your own name.
For a resident, a line in your own name, registered with your ARC number, is what makes this work. A prepaid tourist line or a friend’s number usually won’t pass. That affects:
- Banking. Korean bank apps verify you by text to a number in your name. Without one, you’ll struggle to set up mobile banking at all. Our guide to opening a bank account in Korea covers the rest.
- Shopping, delivery and government sites. Sign-ups typically ask for 본인인증 too.
Two habits save trouble. Make sure the name on your phone account matches your ARC exactly, in the same spelling and order. And if verification fails, call the carrier and ask whether the line is registered to your ARC number.
What to bring to the store
For a regular postpaid plan as a resident, bring:
- Your ARC. This is the document that matters. The government’s Invest Korea guide lists the ARC (or a domestic residence report certificate, 거소신고증, for overseas Koreans) as required.
- Your passport.
- A way to pay in your own name. Postpaid bills are paid from a bank account or card in your name. If you don’t have a Korean account yet, ask the store what they accept before you go.
Your visa type can matter too. Invest Korea notes that the number of lines you can open, whether you can buy a phone on instalments, and whether a deposit is waived all depend on your residence status. If the store asks for something extra, that’s why.
Korea has also been tightening checks on new lines to stop phones being opened in someone else’s name and resold. Lines registered to foreigners are a big part of that problem, and the government has said it will strengthen ID checks for foreigners. Expect your ID to be checked carefully, and don’t open spare lines for friends. There are caps on how many lines one foreigner can open, and the lines stay your legal responsibility.
Big carriers vs budget carriers (알뜰폰)
You have two kinds of provider:
- The big three: SK Telecom, KT, LG U+. They have stores everywhere, sell phones on contract, and bundle home internet. They’re usually the easiest place to open your first resident plan, especially at a branch used to foreign customers.
- Budget carriers, called 알뜰폰 (MVNOs). They don’t own a network. They rent capacity on the big three’s networks and set their own prices. Coverage is generally the same as the network they rent from, and plans are usually much cheaper.
The catch with budget carriers is sign-up. Not every 알뜰폰 accepts foreign customers, some plans exclude foreigners, and the online sign-up often requires 본인인증 — which you can’t do until you already have a verified number. A common route is to open your first line with a big carrier using your ARC. Once you’re settled, compare budget plans and move your number over. Comparison sites let you filter for plans that accept foreigners.
Choosing a plan
Plan names and prices change constantly, so I won’t list them. Ask yourself:
- How much data do you actually use? Check your phone’s usage stats from home. Many people pay for unlimited data and use a fraction of it, especially with Wi-Fi at home and work.
- Are you buying a phone with the plan? Phones on contract tie you to that carrier for a set period, with a penalty if you leave early. If your phone is unlocked, a SIM-only plan keeps you flexible.
- How long are you staying? Don’t sign a long contract if your visa ends sooner.
- Do you need home internet? Bundling it with a big carrier can bring the total down.
Before signing anything, ask for the monthly price after any promotion ends, the contract length, and the early termination fee.
Before you leave Korea
Phone lines in a foreigner’s name are linked to immigration records. Since 2021, lines belonging to foreigners who have left the country can be suspended after notice. Carriers have also suspended lines whose owner’s stay has expired until the owner re-verifies their ID. If you’re leaving for good, cancel the line properly. If you’re keeping a Korean bank account, think first: losing the number can lock you out of your banking app. Our guide to sending money from Korea abroad covers keeping the account usable after you go.
The quick version
Visiting: get a prepaid SIM or eSIM with your passport, or use roaming, and check that your phone is unlocked. Living here: use a prepaid line until your ARC arrives, then open a postpaid plan in your own name with your ARC, passport, and a bank account or card in your name. That number is what banks and apps use to verify you, so don’t skip it. Start with a big carrier, then compare budget carriers (알뜰폰) once you’re settled. Choose a plan by how much data you really use, and check the contract length.
Carrier rules for foreigners change often, especially ID checks. If a store asks for something not listed here, ask what they need and bring it next time.
