Big buckets · no network named · a Trustpilot history
Yesim in South Korea
Yesim wins Korea at exactly two sizes, 20GB and 30GB, and at 1GB for a whole month. It tells you nothing about which Korean network you get or where its unlimited plan slows down, and Trustpilot switched its score off once in 2026. All of it is below.
Every Yesim South Korea plan USD, checked September 2026
| Plan | Price | Per GB | Notes |
|---|---|---|---|
| 1GB / 30 days | $3.00 | $3.00 | A whole month for one cent more than GigSky's 7-day 1GB. The best emergency-line price on the site. |
| 10GB / 30 days | $19.20 | $1.92 | The most expensive 10GB of the four we link. GigSky is $17.79, Saily $18.99, Airalo $19.00. |
| 20GB / 30 days | $27.96 | $1.40 | Cheapest 20GB we can link. Airalo is $29 for 15 days or $30 for 30; Saily $29.99. |
| 30GB / 30 days | $35.04 | $1.17 | Nobody else we link sells 30GB for Korea. The next step up is Airalo's 50GB at $49. |
| Unlimited / 1 day | $4.20 | n/a | Yesim states a fair usage policy and prints no daily gigabyte figure. Trustpilot reviewers describe a 5 Mbps ceiling; that is a customer report, not a term. You cannot know what you bought. |
| Unlimited / 3 days | $12.19 | n/a | |
| Unlimited / 5 days | $20.32 | n/a | |
| Unlimited / 7 days | $28.45 | n/a | |
| Unlimited / 10 days | $34.77 | n/a | |
| Unlimited / 15 days | $45.29 | n/a | |
| Unlimited / 30 days | $66.20 | n/a |
Yesim sells no 3GB or 5GB for Korea, so the ladder jumps from 1GB straight to 10GB. Every plan is data-only with no SMS or Korean number; hotspot is available. Prices are from Yesim's own Korea page in USD, checked September 7, 2026.
Yesim is the Korea eSIM for 20GB and 30GB and for almost nothing else
Two weeks in Korea with Instagram, TikTok and Naver Map running most of the day comes to roughly 10GB, using the usage estimates on our data page. A month of the same is 20GB. A month with a laptop on hotspot in the evenings is 30GB or more. That is where Yesim lives.
At 20GB, Yesim's $27.96 beats Airalo's $30 for the same 30 days by $2.04, and Saily's $29.99 by $2.03. At 30GB there is no comparison to make because no other brand we can link sells 30GB for Korea. The nearest thing is Airalo's 50GB at $49, which is $14 more for 20GB you may never touch, or two Yesim 20GB plans, which is worse.
Now the part we do not skip. Ubigi, which we cannot link and earn nothing from, sells 25GB for $25 over 30 days on SK Telecom and LG U+. That is $2.96 less than Yesim's 20GB for 5GB more, on a named network. If 25GB is your number, Ubigi wins and the only reason to buy Yesim over it is the 30GB size or your own preference. The Ubigi review is here. Nomad, also unlinked, sells 50GB for $39.
The 1GB plan deserves its own sentence. $3.00 for a gigabyte that lives 30 days is the cheapest long-validity spare line on the site: install it next to your main eSIM and forget about it until the evening your main plan dies in Hongdae.
If your month needs 20GB or 30GB and you want a link we can stand behind, this is the one. If it needs 10GB, buy GigSky and save $1.41.
See Yesim Korea plans Work out how much data you needThe Trustpilot history, told once and in full a restored score is not a clean one
Where it stands. As of September 7, 2026 the score is back: 4.3 out of 5 across 2,943 reviews, with no suspension banner on the profile. The review base is the smallest of any brand we link. Saily has 30,662 reviews, Airalo 42,273, GigSky 6,288. A 4.3 on 2,943 reviews is a thinner signal than a 4.3 on 6,288, and a far thinner one than Saily's 4.7 on 30,662.
What we make of it. The enforcement did its job and the profile came back. That is the good outcome, and it is not the same as the suspension never having happened. A company whose reviews were once cleaned out from under it is a company that once had a reason to want better reviews than it had earned.
What we do about it. Yesim stays on the site because its prices are real and at 20GB and 30GB nobody we can link beats them. This history sits next to its name in every table, marked with a footnote. It pays us 18 per cent, and that is exactly why the history is not going anywhere. For contrast: Holafly, which we do not link, carries an active Trustpilot banner about past guideline violations as of September 7, 2026. Yesim's banner is gone. Holafly's is not.
Yesim against the rest of the Korea field size by size
| Yesim | Airalo | GigSky | Saily | Ubigi¹ | |
|---|---|---|---|---|---|
| 1GB | $3.00 / 30d | $4.00 / 3d | $2.99 / 7d | $3.99 / 7d | $3.00 / 7d |
| 5GB | none | $10.00 / 7d | $10.29 / 30d | $10.99 / 30d | none |
| 10GB / 30 days | $19.20 | $19.00 | $17.79 | $18.99 | $14.00 |
| 20GB / 30 days | $27.96 | $30.00 | none | $29.99 | 25GB $25.00 |
| 30GB | $35.04 | none (50GB $49) | none | none | none |
| Unlimited, 30 days | $66.20 | $69.00 | none | $71.99 | $49.00 (60GB total) |
| Unlimited cap published | no | 3GB/day, then 1 Mbps | 3.5GB/day in the name | 5GB/day | total GB, then 2 Mbps |
| Korean network | not published | SK Telecom | not published | not published | SKT + LG U+ |
| Trustpilot | 4.3 · 2,943² | 4.1 · 42,273 | 4.3 · 6,288 | 4.7 · 30,662 | 4.1 · 45,280 |
| Pays this site | 18% | 12% | 20% | 15% | nothing |
¹ Ubigi is in no affiliate program we belong to and is never linked here; its store is cellulardata.ubigi.com. ² Score suspended in 2026 during a fake-review cleanup, since restored. Prices USD, checked September 7, 2026.
Yesim takes four rows: cheapest 1GB with a month of validity, cheapest 20GB, the only 30GB, and the cheapest 30 days of unlimited among the brands we link. The unlimited win carries an asterisk the size of the plan. Yesim will not say how much full-speed data a day it includes, so $66.20 for an unknown allowance is not obviously cheaper than Airalo's $69 for a printed 3GB a day, or Saily's $71.99 for a printed 5GB.
And every "unlimited" on this table loses to the Korean carriers. LG U+'s tourist eSIM is ₩27,500 (≈$20) for 5 days with no speed cap at all; SK Telecom's via krsim is $20.70 for 7 days with no fair-use policy. The cost is a passport registration after landing. The unlimited page lays all of it out.
Where Yesim will and will not tell you what you are on place by place, from published data and traveler reports
We have not run speed tests in Korea and will say so until we have. These rows use MSIT's official 2025 measurements, Opensignal's December 2025 report and carrier statements. Yesim publishes no Korean network, only a promise that its "SwitchLess" system picks the fastest available one, so every row below starts from that silence.
| Place | Network under Yesim | What the data says |
|---|---|---|
| Seoul | not published | MSIT's big-city 5G average is 1,090 Mbps on all three carriers, so a 30GB bucket will drain as fast as you let it. Subway averages 929 Mbps, though 13 of MSIT's 32 weak-5G zones are subway sections. |
| Busan | not published | Gimhae airport still has KT, SKT and LG U+ counters open 06:00 to 22:00, unlike Jeju. A Yesim eSIM installed at home means you never need them; small-city 5G averages 996 Mbps. |
| KTX Seoul to Busan | not published | MSIT measured 393 Mbps on high-speed rail with only 81 per cent of readings meeting the HD-streaming bar; 19 of 32 weak-5G zones are rail sections. That is the one place a 20GB plan gets used slowly, on every carrier, whichever one Yesim lands on. |
| Jeju | not published | Jeju airport has had no carrier counters since the end of June 2026, so install before you fly. Travelers report full 4G and 5G on all three carriers including Hallasan trails; Yesim's silence costs nothing here that we can find. |
| Jirisan | not published | Rural 5G averages 617 Mbps per MSIT. Guides give SK Telecom the edge in the mountains and note LG U+ has no 3G fallback so drops to no-service faster in deep valleys. Without a named network you cannot plan around either; SKT's edge is reputation, not measurement. |
| Ferry to Ulleungdo | not published | KT's maritime LTE reaches about 100 km offshore and KT runs LTE plus 5G on Ulleungdo itself. Other carriers' sea coverage is unverified. Whether Yesim's "fastest available network" includes KT at sea is not something Yesim says. |
If you want the network named, Airalo shows SK Telecom. The network page explains why in Korea that matters less than anywhere else we cover, except on the train.
Buying and activating Yesim for Korea four steps
- Buy on Yesim's website at home on wifi. Check the currency selector shows USD before you compare against the table above; Yesim's Korea page served us USD on September 7, 2026, and that is where every price here comes from.
- Know what the unlimited plan is. Yesim gives no daily figure anywhere. If you need to plan around a number, Saily prints 5GB a day and Airalo prints 3GB a day then 1 Mbps. If you need no cap at all, that is the Korean carriers on the carrier page.
- Install the profile before you fly. The 30 days start when the eSIM first connects in Korea, not at purchase, so there is no penalty for installing a week early.
- On landing at Incheon: Yesim line on for data, US line on for calls and texts with data roaming off. The phone will show SKT, KT or LG U+ in Latin letters, which is the only way you will ever learn which network Yesim gave you. If nothing connects in five minutes, toggle airplane mode, then try manual network selection. Full setup and fixes.
Buy Yesim for Korea if, skip it if the short version
Buy it if
- You need 20GB for a month and want the cheapest link on the site: $27.96.
- You need 30GB. Nobody else we link sells it for Korea, and $35.04 is $1.17 a gigabyte.
- You want a $3.00 spare gigabyte that stays alive for 30 days next to your main eSIM.
- You have read the Trustpilot section and the history does not change your mind.
Skip it if
- You need 10GB or less. GigSky is $1.41 cheaper at 10GB and Yesim sells no 3GB or 5GB at all.
- You want unlimited with a cap you can read. Yesim publishes none. Saily publishes 5GB a day.
- You want to know the network before you pay. Only Airalo tells you, and it is SK Telecom.
- You are happy buying from a brand we cannot link. Ubigi's 25GB is $25 on SK Telecom and LG U+, reviewed here.
Yesim South Korea questions short answers
Is Yesim safe to use for Korea?
It sells real plans that people use in Korea without incident, and it takes standard payment. The thing to know: Trustpilot suspended its score in 2026 during a fake-review cleanup, then restored it. As of September 7, 2026 the profile shows 4.3 across 2,943 reviews with no banner. That is a recovered profile, not an unblemished one, and it sits on the smallest review base of any brand we link.
Which network does Yesim use in South Korea?
Yesim does not publish it. Its Korea page says its "SwitchLess Networks" system connects you to the fastest available network, including 5G, and never names SK Telecom, KT or LG U+. The phone will show you after you land. Airalo is the only brand we link that names a network, SK Telecom.
Does Yesim have unlimited data for Korea?
Yes, from $4.20 for one day to $66.20 for 30, the cheapest 30-day unlimited among brands we link. It is also the only one of them that publishes no daily allowance at all; Yesim says only that speed may be limited under the operator's fair usage policy. Trustpilot reviewers describe a 5 Mbps ceiling, which is a customer report, not a published term. LG U+'s own tourist eSIM has no cap and costs about $20 for 5 days.
What is the cheapest 20GB or 30GB eSIM for Korea?
Among brands we link, Yesim at $27.96 for 20GB and $35.04 for 30GB, both over 30 days, checked September 7, 2026. Airalo's 20GB is $30, Saily's $29.99. Unlinked: Ubigi sells 25GB for $25 and Nomad 50GB for $39, and we earn nothing from either.
Is Yesim cheaper than Airalo for Korea?
At 1GB yes, $3.00 for 30 days against $4.00 for 3. At 10GB no, $19.20 against $19.00. At 20GB yes, $27.96 against $30.00 over the same 30 days. At 30 days of unlimited yes on the sticker, $66.20 against $69, but Airalo prints a 3GB-a-day cap and Yesim prints nothing, so you are comparing a known quantity with an unknown one.
How much does this site earn if I buy Yesim?
18 per cent of the sale through Travelpayouts, the second highest rate of the four brands we link. It never changes your price. It is also why the Trustpilot history is written on this page and not hidden. How we test and what we earn.
The only 30GB we can link for Korea
$35.04 over 30 days, or 20GB for $27.96, the cheapest big buckets among the brands we link. Yesim names no Korean network, prints no unlimited cap, and had its Trustpilot score suspended in 2026 before it was restored. It pays this site 18 per cent. All of that is on this page on purpose.
See Yesim Korea plansSources & freshness: Plan prices from Yesim's own Korea page in USD on September 7, 2026, before promo codes. Network: not published on that page; the "SwitchLess Networks" wording is Yesim's. Unlimited fair-use wording from the same page; the 5 Mbps figure is from Trustpilot customer reviews and is not a published term. Trustpilot 4.3 across 2,943 reviews with no banner, checked September 7, 2026; the 2026 suspension during a fake-review cleanup is recorded in our provider notes. Speed figures: MSIT 2025 communications quality evaluation (korea.kr, December 2025) and Opensignal South Korea, December 2025. Jeju counter closures: Newsway, May 2026. Commission rate: our Travelpayouts dashboard. We have not run speed tests in Korea. How we test.