Unlimited Plan Throttle Speeds Explained — What 400kbps, 1Mbps and 5Mbps Actually Get You
by SelPl Editorial Team
You signed up for an "unlimited" plan and now video calls buffer? Almost every Korean "unlimited" plan throttles your speed (QoS) after you use a set amount of data. This guide shows what you can actually do at each throttle speed — so you can choose a plan that fits your real usage, not the marketing label.
How Korean "Unlimited" Plans Really Work
A plan labelled "100GB + 5Mbps" means:
- Up to 100GB: full LTE/5G speed (typically tens to hundreds of Mbps)
- After 100GB: capped at 5Mbps (Netflix HD yes, 4K barely)
Truly unlimited plans exist but are rare and expensive. Most "unlimited" plans follow this base + throttle pattern.
Side-by-Side: What Each Speed Can Do
| Task | 400kbps | 1Mbps | 3Mbps | 5Mbps | Full LTE (20–50Mbps) |
|---|---|---|---|---|---|
| Messaging (text, stickers) | ✅ | ✅ | ✅ | ✅ | ✅ |
| Sending photos on chat | ⚠️ 10–30s | ✅ 3–5s | ✅ | ✅ | ✅ instant |
| Web / news browsing | ✅ slow | ✅ | ✅ | ✅ | ✅ |
| Maps (Google, Naver) | ⚠️ slow tiles | ✅ | ✅ | ✅ | ✅ |
| Voice calls (VoIP) | ✅ | ✅ | ✅ | ✅ | ✅ |
| Music streaming (Spotify) | ⚠️ low quality | ✅ 128kbps | ✅ 320kbps | ✅ 320kbps | ✅ high |
| YouTube 144p | ✅ | ✅ | ✅ | ✅ | ✅ |
| YouTube 480p | ❌ | ✅ tight | ✅ | ✅ | ✅ |
| YouTube 1080p | ❌ | ❌ | ⚠️ | ✅ | ✅ |
| YouTube 4K | ❌ | ❌ | ❌ | ⚠️ | ✅ |
| Video calls (FaceTime, Zoom) | ❌ | ⚠️ low res | ✅ SD | ✅ HD | ✅ HD |
| Netflix SD (480p) | ❌ | ⚠️ | ✅ | ✅ | ✅ |
| Netflix HD (1080p) | ❌ | ❌ | ⚠️ | ✅ | ✅ |
| Netflix 4K | ❌ | ❌ | ❌ | ⚠️ | ✅ (≥15Mbps) |
What Each Speed Feels Like Day to Day
💨 400kbps — The strictest throttle
Comfortable: messaging, news reading, email. Not so much: 144p YouTube is borderline, photo-heavy group chats lag, Instagram/TikTok scrolling feels broken.
One-liner: fine if you live in messages; video is basically gone.
⚡ 1Mbps
Comfortable: 480p YouTube (most lectures, news clips), music streaming, web, maps. Not so much: anything above 1080p buffers, video calls are low-res.
One-liner: if you skip full-HD video, you barely feel the limit.
🚀 3Mbps
Comfortable: 720p YouTube, Netflix SD, SD video calls, music and podcasts at full quality. Not so much: 1080p buffers sometimes.
One-liner: solid for daily streaming if you don't insist on HD.
🚀🚀 5Mbps
Comfortable: 1080p YouTube/Netflix, HD video calls, live streams. Not so much: 4K streaming pushes the edge (≥15Mbps recommended).
One-liner: unless you need 4K, it's practically invisible.
Which Speed Matches Your Day?
| Usage pattern | Minimum speed | Plan tier |
|---|---|---|
| Messaging, web, maps only | 400kbps–1Mbps | Budget plans throttle fine |
| YouTube / music heavy | 1–3Mbps | Mid-tier |
| Video calls / meetings | 3Mbps | Mid-upper |
| Constant HD Netflix / YouTube | 5Mbps | Upper |
| 4K or large downloads | 15Mbps+ | XL or true unlimited |
FAQ
Q. Why do "unlimited" plans slow me down? A. Fair-use policy (FUP) to prevent network congestion. All three Korean majors and most MVNOs do it.
Q. How long does the throttle last? A. Usually until your monthly billing reset — typically the 1st of each month.
Q. Is "up to 5Mbps" a guarantee? A. It's the cap, not a floor. Peak hours can be slower.
Q. Does it matter if I use WiFi most of the time? A. Not really. If you're mostly on WiFi at home/work, throttle speeds are often enough.
Q. Are there truly unlimited plans? A. A few, but they're expensive (₩50,000+). Overkill for most users.
Summary
- "+ NMbps" on an unlimited plan is your post-quota cap
- 400kbps → messaging OK, forget video
- 1Mbps → 480p YouTube is smooth
- 5Mbps → HD streaming works fine
- Match the throttle to your usage and save serious money
Not sure which plan fits? Try Get Recommendations to see options matched to your habits.