Smart Phone (스마트폰): SIM Card(유심) and Phone Paln

South Korea's mobile network is exceptional. 5G coverage reaches approximately 93% of the population — the highest rate in the world. LTE speeds in Korean cities are among the fastest globally. And the cost, relative to the speed and coverage, is competitive. Getting a Korean SIM card or phone plan is one of the first practical tasks on arrival — and one of the easier ones, once you understand the options.

두 가지 선택 (Two Main Options)

선택 1: 선불 유심 (Prepaid SIM)

선불 유심 (seonbul yusim, prepaid SIM) requires no contract, no credit check, and minimal documentation. It's the fastest way to get a Korean number.

구매 장소 (Where to buy):

• 인천공항 (Incheon Airport): Booths from all three major carriers immediately after customs — the most convenient option on arrival

• 편의점 (Convenience stores): GS25, CU, 7-Eleven sell prepaid SIMs with data packages

• 통신사 대리점 (Carrier stores): SK텔레콤 (SK Telecom), KT, LG유플러스 (LG U+) retail stores

필요 서류 (Required documents):

• Passport — for short-term visitors without an ARC

• 외국인등록증 (ARC, Alien Registration Card) — for registered foreign residents; enables more plan options

선불 요금제 (Prepaid plan options):

Prepaid plans typically do not include domestic calls — or include limited minutes. If you need calls, check the specific plan before purchasing.

선불의 한계 (Prepaid limitations): Prepaid numbers are sometimes not accepted by Korean banking apps and government portals — which require a number registered in your name under a postpaid plan. If you plan to open a bank account or use government services, a postpaid plan is preferable.

선택 2: 후불 요금제 (Postpaid Plan)

후불 요금제 (hubul yoeunje, postpaid plan) is a monthly contract — the standard plan for residents. It requires an ARC.

3대 통신사 (Three major carriers):

알뜰폰 (Budget Carriers / MVNOs):
알뜰폰 (alddeuripon) — Mobile Virtual Network Operators — use the infrastructure of the big three carriers but offer significantly lower prices. Recommended for cost-conscious residents.

Popular 알뜰폰 providers:

알뜰폰 요금제 예시 (MVNO plan examples):

3대 통신사 무제한 요금제 (Big three unlimited plans):
SK / KT / LG U+ 5G unlimited: approximately ₩69,000–₩89,000/month

Tip — 알뜰폰 추천 (MVNO recommendation): For most foreign residents who want a reliable postpaid number at reasonable cost, 헬로모바일 (Hello Mobile) is frequently recommended in expat communities — it uses the KT network, offers English customer support, and has a foreigner-specific sign-up process. Plans start at approximately ₩15,000/month.

개통 과정 (How to Sign Up)

통신사 매장 방문 (Visiting a Carrier Store)

필요 서류 (Required documents):

• 외국인등록증 (ARC) — mandatory for postpaid plans

• 여권 (Passport)

• 은행 계좌 (Bank account) for automatic payment — or a Korean credit/debit card

• 번호이동 서류 (Number porting documents) — if transferring an existing Korean number

The process at a store takes approximately 20–30 minutes. Staff at major carrier stores in central Seoul and expat neighborhoods often have some English capability.

온라인 개통 (Online Sign-Up)

Most carriers and MVNOs allow online sign-up — particularly 알뜰폰 providers. The process is in Korean but navigable with a translation app. You'll need your ARC number and bank account details.

유심 배송 (SIM delivery): For online sign-ups, the SIM is delivered to your address within 1–3 business days.

번호이동 (Number Portability)

If you already have a Korean number and want to switch carriers while keeping the same number, Korean law guarantees 번호이동 (number portability). You can switch at any store of the new carrier with your ARC and passport — the process takes approximately 30 minutes and takes effect the same day in most cases.

로밍 vs. 현지 유심 (Roaming vs. Local SIM)

For visits of less than 90 days:

eSIM: Korea's three major carriers and several MVNOs now support eSIM — downloadable directly to compatible devices without a physical SIM. Increasingly popular for visitors with newer smartphones.

Key Facts