K-Internet & Mobile Glossary 2025
한국 통신·모바일·데이터·공공 Wi-Fi 용어 사전 (EN·KR)
Korea’s internet is fast — but the words can feel like a maze. Here are the real terms you’ll meet in phone stores, carrier apps, and public Wi-Fi screens, explained simply.
1) Mobile Plans & Data Basics (요금제·데이터 기본)
Your monthly subscription. It usually bundles talk, text, and data in one price.
Unlimited data — but many plans slow down after you use a high-speed limit.
Think “unlimited with a speed rule.”
The monthly high-speed data amount included in your plan (e.g., 30GB).
When your data speed drops after the cap. Apps still work, just slower.
A common mid-tier 5G plan name from carriers. Not a technical standard — just branding.
4G plan. Often cheaper and sometimes more stable outside big cities.
Discounted plans for teens/students. Sometimes include app perks.
Lower-cost plans for older customers, often with simple features.
How many call minutes are included per month. Many plans say “unlimited calls.”
Monthly SMS allowance. Most plans include unlimited texting.
2) Data Usage & Add-ons (데이터 사용·추가 기능)
Using your main plan’s data on another device (tablet, smartwatch, second phone).
Sending some of your data to another person through the carrier app.
Small extra data packs you buy (1GB, 2GB, etc.).
Temporary unlimited-style data for a day or week. Good for short trips.
Sharing your phone’s internet with your laptop or another phone.
Paying extra to restore or increase speed after throttling.
Certain apps don’t count against your data cap (carrier-specific).
Using your Korean SIM abroad. Fees depend on country/plan.
Fixed-price roaming bundle for travel (e.g., 3 days, 5GB).
Small carriers (MVNO) using big carriers’ towers inside Korea.
3) SIM, eSIM & Activation (유심·eSIM·개통)
The small physical chip that connects your phone to a carrier.
A digital SIM built into your phone. Activate by scanning a QR code.
Turning your SIM on so calls/data start working.
Registering your ID (passport/ARC) to legally use a Korean SIM.
You pay first, then recharge. Easy for tourists. No long contract.
Monthly bills. Usually needs a Korean ID + credit check.
Activating eSIM by scanning a carrier QR code from email/app.
Two phone numbers on one device (e.g., SIM + eSIM).
Keeping your number while switching carriers.
A phone restricted to one carrier. Must be unlocked to use another SIM.
4) Carriers & MVNO System (통신사·알뜰폰 구조)
Main telecom companies: SKT, KT, LG U+. They own the network towers.
Cheaper providers that rent networks from big carriers. Same signal, different price.
A map showing where 5G works. Big cities are strong; rural areas may be LTE.
4G coverage. Usually wider than 5G in mountains or small towns.
How strong your reception is. Weak signal = slower internet and dropped calls.
Temporary network failure. Usually fixed quickly, but can cause big news.
Discount when multiple family lines share one carrier account.
Loyalty discount for subscribers who stay with one carrier.
Paying for the phone monthly instead of upfront.
Official shop where you buy SIMs, change plans, or get repairs.
5) Wi-Fi & Public Networks (와이파이·공공 네트워크)
Free Wi-Fi offered by city/government in stations, streets, and parks.
A common hotspot name you’ll see in many places. Some versions are open, some need login.
LG U+ public hotspots. Often available in cafés and malls.
Wi-Fi requiring login or certificate — safer than fully open networks.
The webpage that pops up before you can fully connect to Wi-Fi.
Many cafés/restaurants have a password on the counter or receipt.
Some plans limit hotspot use. The carrier app may warn you.
Newer routers may run IPv6 only. Older devices sometimes fail to connect.
Calls made through Wi-Fi when mobile signal is weak.
Places where signal is weak or blocked (basements, tunnels, mountains).