Travel eSIM or Korean prepaid SIM for a stay longer than 30 days?

Is a travel eSIM or a Korean prepaid SIM better for a stay of more than 30 days?

For most stays longer than a month, a Korean prepaid SIM is the better main line, because it gives you a Korean number and a travel eSIM doesn't. A travel eSIM is still useful for the first days, before you've reached a phone shop, and as the whole answer for a stay of up to 30 days that never needs a Korean number. Once you're staying past 90 days and have an Alien Registration Card, a postpaid contract opens up as well. The facts below come from the Korean government's Easy Law guide for international students (찾기쉬운 생활법령정보, run by the Ministry of Government Legislation), KT's English online shop and Kedanto's own Korea page, all checked on 30 September 2026.

How long can a Kedanto Korea eSIM cover?

The longest plan on Kedanto's Korea page lasts 30 days, and every plan is data only, with no phone number and no SMS. The daily plans run from 3 to 15 days, with 1GB or 2GB a day. The total-data plans give 3GB, 5GB, 10GB, 20GB or 50GB to use within 30 days. The 50GB plan is listed at $24.38 USD and the 10GB plan at $7.34 USD (English page, checked 30 September 2026). The page doesn't mention a top-up or an extension, so a stay of 60 or 90 days would mean buying a new plan each time the old one ends. What happens when a plan runs out partway is covered in daily plans slow down, total plans stop.

The same page adds a point that matters more on a long stay than on a short trip: the eSIM's internet traffic exits through Singapore, "so some Korean websites and apps may treat you as connecting from abroad." For a week of maps and messaging that rarely shows. For a semester of Korean banking, delivery and university apps, it's one more reason to have a Korean line.

What do you need to open a Korean prepaid SIM?

Your passport. Prepaid is the one kind of Korean mobile plan a foreigner can open without an Alien Registration Card. The Easy Law guide for international students sets out the three routes side by side, citing the guidebook for international students published in December 2025 by the National Institute for International Education (국립국제교육원) under the Ministry of Education:

• Prepaid (선불 요금제): passport only. You charge the balance before you use it. Pros listed: no contract and a simple sign-up. Cons: recharging again and again, and "limited benefits" on data speed and allowance.
• Postpaid (후불 요금제): Alien Registration Card (외국인등록증) and passport. You pay monthly after use, and a contract is required.
• Budget carriers, called MVNOs (알뜰폰): Alien Registration Card and passport, opened online through the MVNO's own website. Cheaper plans and no contract, but opening an account "may be restricted depending on the carrier," and foreign-language support is limited.

The guide recommends prepaid for students on short stays, and postpaid plans opened at SKT, KT or LG U+ stores for students on long stays. It also notes that the documents differ from carrier to carrier, so ask the one you choose before you go.

KT's English online shop spells out its own version. Its LTE Welcome Prepaid plans are "available for only foreign customers," with the line "Sign up easily with just your passport!" KT's page on what you need confirms that "Prepaid lines of service can also be signed up with a standard passport," and that each person can hold one prepaid and one postpaid KT line.

How long does a prepaid SIM last if you only have a passport?

At KT, 90 days from activation, unless you verify your identity again at a store. KT's page on required documents gives two service periods for prepaid lines: "Activation with a Passport: Service available for 90 days from activation," and with an Alien Registration Card, service runs until the card expires. The prepaid plan page says the same in other words: without a foreigner registration number, "you can only use the service for 90 days," but "if you visit a store for real-name verification, your usage period can be extended."

The 90 days line up with Korea's own registration rule. Easy Law's English guide for foreign students says: "Any alien who stays in the Republic of Korea in excess of 90 days from the date of entry shall complete alien registration," and that registration must be completed within 90 days of entry, at the immigration office for the area where you live. So a student who arrives, opens a KT prepaid line with a passport and registers on time has the card in hand to extend the line in time.

What does a Korean prepaid plan cost, and how does renewal work?

KT's prepaid plans for foreigners cost 35,000, 45,000 or 55,000 KRW for 30 days, VAT included, as listed on KT's English shop on 30 September 2026. Each comes with 200 minutes of calls and 200 texts:

Renewal is by recharge. KT says you can recharge at KT Plaza, KT stores, KT.com, My KT, by calling ARS 1500 or through the KT Customer Center. Each recharge amount buys a validity period: 5,000 KRW buys 30 days, 10,000 KRW buys 60 days, and 50,000 or 55,000 KRW buys 365 days. When the validity period ends, any balance left is lost, and KT gives no refunds on charged amounts.

KT also explains what happens if you stop recharging. From the day the balance or validity runs out, or your permitted stay ends, you can't make calls but can still receive them. After 14 days, incoming calls stop too. After 44 days, the plan is terminated automatically. That's worth knowing before your last month, because KT separately asks foreign customers to cancel their service before leaving Korea, and says cancellations have to be done in person at a KT store.

The prices don't compare like for like with a travel eSIM. KT's price includes a Korean number, calls and texts. Kedanto's 50GB for 30 days has far more data but no number at all. If you're weighing data alone, work out your month on the data calculator.

Why does a Korean number matter more on a long stay?

Because a long stay runs into Korean sign-ups that a short trip can skip. Taxis on the street, Tmoney cards and some restaurant bookings work without a Korean number. Other services send a code to a 010 number, and bank and government identity checks go further, requiring a line registered in your own name with a Korean carrier. Which is which is sorted out in what works in Korea without a Korean phone number.

The Easy Law guide puts the case for a Korean line plainly: opening one makes communication and administrative and financial services easier to use during your studies. Kedanto's eSIM can't help with any of that, because it has no number. If you keep your home SIM on while you're in Korea, codes sent to your home number still arrive. The setup for that is in getting verification texts on your home number.

Is a postpaid contract worth it once you have your card?

If you're staying for months and want Korean discounts and a monthly bill, yes. That route opens only after you have an Alien Registration Card. Both the Easy Law guide and KT list the Alien Registration Card as the document for a postpaid line. KT adds that "At least 90 days must be left on your visa to subscribe for KT mobile services," and that monthly charges are paid by auto-debit from a Korean bank account or a Korean credit card. So a postpaid plan usually comes after you've registered and opened a Korean bank account, not in your first week. Easy Law notes that postpaid plans cost relatively more and need a contract, while MVNO plans are cheaper and contract-free.

If you'd rather ask in your own language first, the Easy Law guide lists the carriers' foreign-language lines. SKT is 080-011-6000 (ask for the foreign-language service, English, Chinese or Japanese). KT's team for foreign customers is 02-2190-1180 (English, Chinese, Japanese). LG U+ is 1544-0010 (ask for English).

What does a sensible first 90 days look like?

1. Before you fly: install a travel eSIM on Wi-Fi at home, so maps and messaging work from the arrivals hall. A total-data plan of up to 30 days covers the gap.
2. In your first week: take your passport to a carrier store and open a prepaid line, if your phone can hold it alongside the eSIM or you're ready to switch over. You now have a Korean number for sign-ups.
3. Within 90 days of entry: register at your local immigration office, if you're staying longer than 90 days.
4. Once the card arrives: bring it to the store to extend your prepaid line past its passport-only period, or move to a postpaid or MVNO plan.

If your stay is 30 days or less and every app you need works with your home number, a travel eSIM on its own is simpler, and you have nothing to cancel before you go. Kedanto's plans are on the Korea eSIM page.