One eSIM and you're set,
a Korean number is rarely needed
One eSIM before you fly — you rarely need a Korean number.
For most divers the answer is: buy a data eSIM before departure → activate it the moment you land. No airport queue, data before you clear immigration, and your home number stays alive so you can use KakaoTalk and WhatsApp. A Korean 010 number is rarely needed — only for Korean bank, fintech, and government identity verification.
One eSIM and you're set
Three-line summary — with a data eSIM, maps, translation, taxis, and KakaoTalk contact with dive shops all work on data alone.
- Buy a data eSIM before departure → activate on landing. No airport queue; keep your home number for KakaoTalk / WhatsApp.
- A Korean number is rarely needed. A 010 number is only needed for Korean bank, fintech, and government identity verification.
- Cash + backups for remote islands and boats. Ulleung, Dokdo, and West Sea islands have weak signal at sea — get offline maps and translation apps, and the shop's KakaoTalk ID in advance.
Five options — eSIM is usually the answer
2019+ phones, most travellers. No Korean number. Buy online before departure. Cheapest and fastest.
Older / non-eSIM phones. Some plans include voice / a 010 number. Airport counters and convenience stores.
One device shared by the whole group. Daily charging and carrying it around.
Only for a 1–2 day layover. Keeps your home number. Expensive (~$10–15/day).
Ultra-light use. Unstable outdoors and weak security on open networks.
Activate on your first connection after landing
Buy online → receive a QR code → install before departure → activate on your first data connection after landing. Most 2019/2020+ flagships support it, and you leave your home SIM in place to keep your home number.
- The LG U+ official data-only eSIM includes free T-money when you buy 3+ days (pick up at the airport).
- Global apps like Airalo, Saily, and Holafly are data-only too — pick a generous number of days in case of weather delays.
The three carriers and their weakness at sea
SKT, KT, and LG U+ can all be picked up at the arrivals counters at Incheon Airport (T1 exits 6–7 and 10–11, T2 exits 4–5). Nationwide coverage is excellent, but remote islands and the open sea are the weak spots.
- Booking online in advance and picking up at the airport is the smoothest.
- Public WiFi on the subway, in cafés, and on buses is unstable outdoors — don't rely on it for boat diving.
- Global eSIM prices are aggregated for this 2026 guide — check current rates when you buy.
- Carrier rates and pickup locations may change — confirm with official sources.