The one that beats us on price · and pays us nothing
Ubigi in South Korea
Ubigi publishes two Korean networks, sells 10GB for $14, and is owned by an NTT Group company. It is in every table on this site and we cannot take a cent from you for it. This is the full review, including the places where the brands we do sell are genuinely better.
Why an affiliate site reviews a Korea eSIM it cannot sell the short answer
Because Ubigi sits in the 10GB row of every table on this site with the lowest number in it, and a reader who notices that deserves the whole story, not a blank.
We could have left it out. Most comparison pages do, and you can spot them: every brand they name has an affiliate program. We would rather publish the table that survives you checking it against Ubigi's own store, because that is the table you will trust when we do recommend something we earn from.
What follows is a real review. Ubigi wins on price at 10GB and 25GB and on network disclosure. Airalo, which we do sell, wins at exactly 5GB for a week, on app polish, and on running a single named network that happens to be Opensignal's best in Korea. We will not stretch either side of that.
Every Ubigi South Korea plan USD, checked September 2026
| Plan | Price | Per GB | Notes |
|---|---|---|---|
| 1GB / 7 days | $3.00 | $3.00 | One cent more than GigSky's 1GB for the same week. Yesim's 1GB lasts 30 days for the same $3.00. |
| 3GB / 7 days | $7.00 | $2.33 | Cheapest 3GB on the site. GigSky is $8.49 but over 15 days. |
| 10GB / 7 days | $12.00 | $1.20 | A week of heavy use for less than anyone's 10GB month. Airalo's 10GB for 7 days is $18. |
| 10GB / 30 days | $14.00 | $1.40 | Cheapest 10GB on the site by $3.79 over GigSky, $5 over Airalo. |
| 25GB / 30 days | $25.00 | $1.00 | A dollar a gigabyte. Yesim's 20GB is $27.96; Airalo's is $30. |
| Unlimited / 7 days | $25.00 | $1.00¹ | 25GB of full speed for the week, then 2 Mbps. A total, not a daily cap. Printed on Ubigi's plan page. |
| Unlimited / 15 days | $34.00 | n/a | We did not fetch the full-speed total for this one, so it stays blank rather than guessed. |
| Unlimited / 30 days | $49.00 | $0.82¹ | 60GB of full speed for the month, then 2 Mbps. Also a total. |
¹ Per gigabyte of the printed full-speed allowance. Ubigi has no 5GB or 20GB for Korea; the ladder goes 3, 10, 25. Data sharing (hotspot) is allowed on all plans per Ubigi's page. Prices in USD from Ubigi's own plan pages, checked September 7, 2026. None of them are linked.
The 10GB row is the reason this page exists. Fourteen dollars for 10GB over 30 days, on SK Telecom and LG U+, is $1.40 a gigabyte. The cheapest 10GB we can sell you is GigSky at $17.79, which does not tell you its network. If your trip needs 10GB over two or three weeks, Ubigi is cheaper on a named network, and we make nothing saying so.
Ubigi publishes SK Telecom and LG U+ and its parent company is an operator
Ubigi's Korea page lists SK Telecom and LG U+, with 3G, 4G and 5G. That is two of Korea's three carriers, and one of them is the one Opensignal named Best Network in December 2025, with a Coverage Experience score of 9.4 against KT's 9.1 and LG U+'s 8.6.
Among the four brands we can link, only Airalo publishes any network, and it publishes one: SK Telecom. GigSky, Saily and Yesim say nothing. So on disclosure Ubigi and Airalo are the two honest brands on the site, and Ubigi's pairing gives the phone a second carrier to fall back to. Whether the fallback ever triggers in practice, in a country where all three carriers post 5G averages around 1,000 Mbps, is a fair question. The network page argues it matters less in Korea than anywhere else we cover, except on the KTX.
The reason Ubigi tends to have carrier agreements it can name is corporate. Ubigi is the consumer brand of Transatel, a French mobile operator owned by the NTT Group. It is an operator selling eSIMs, not a marketing company reselling capacity, and it publishes its networks the way operators do.
The con, since every brand here gets one in plain text: Ubigi's Trustpilot score is 4.1 across 45,280 reviews, checked September 7, 2026. That is a large base and a middling score, tied with Airalo's 4.1 and well under Saily's 4.7. Two named networks do not buy you a better support desk.
The Ubigi unlimited plan is a total allowance, not a daily one which is a different product
Every travel-eSIM unlimited we cover for Korea is a daily cap in disguise: 5GB a day at Saily, 3.5GB at GigSky, 3GB at Airalo, 2GB at Nomad, and no number at all from Yesim or Holafly. Ubigi does it differently. Its 7-day unlimited is 25GB of full speed for the whole week, then 2 Mbps. Its 30-day plan is 60GB for the month, then 2 Mbps.
That changes how you use it. A daily cap punishes the one heavy day, the one where you upload a Seoraksan hike and stream a K-drama on the bus back. A total allowance lets that day cost 8GB as long as the rest of the week is lighter. Spread evenly, 25GB over 7 days is about 3.6GB a day, more than Airalo's 3GB and a little more than GigSky's 3.5GB, and Ubigi prints the after-cap speed, 2 Mbps, where GigSky prints nothing.
Two honest caveats. First, if you are the kind of user who will burn 25GB by Wednesday, you spend Thursday to Sunday at 2 Mbps, which is fine for Naver Map and KakaoTalk and not fine for video. A 5GB daily cap at Saily would have been kinder to you. Second, the Korean carriers make all of this moot: LG U+'s tourist eSIM is ₩27,500 (≈$20) for 5 days with no speed cap at all, and SK Telecom's via krsim is $20.70 for 7 days with no fair-use policy. Both need a passport registration after landing, which Ubigi does not. The unlimited page ranks every cap.
Ubigi against the four we can sell honestly, both directions
| Ubigi | Airalo | GigSky | Saily | Yesim¹ | |
|---|---|---|---|---|---|
| 3GB / 7 days | $7.00 | $9.00 | $8.49 / 15d | $8.99 / 30d | none |
| 5GB / 7 days | none | $10.00 | $10.29 / 30d | $10.99 / 30d | none |
| 10GB / 7 days | $12.00 | $18.00 | none | none | none |
| 10GB / 30 days | $14.00 | $19.00 | $17.79 | $18.99 | $19.20 |
| 20 to 25GB / 30 days | 25GB $25.00 | 20GB $30.00 | none | 20GB $29.99 | 20GB $27.96 |
| 30GB or more | none | 50GB $49.00 | none | none | 30GB $35.04 |
| Unlimited, 7 days | $25.00 | $29.00 | $27.99 | no 7-day size | $28.45 |
| Unlimited cap | 25GB total, then 2 Mbps | 3GB/day, then 1 Mbps | 3.5GB/day, after-speed not published | 5GB/day | not published |
| Korean network | SK Telecom + LG U+ | SK Telecom | not published | not published | not published |
| Free trial | no | no | 100MB / 7 days | no | no |
| Trustpilot | 4.1 · 45,280 | 4.1 · 42,273 | 4.3 · 6,288 | 4.7 · 30,662 | 4.3 · 2,943 |
| We earn a commission | no | 12% | 20% | 15% | 18% |
¹ Yesim's Trustpilot score was suspended in 2026 during a fake-review cleanup and has since been restored. Prices USD, checked September 7, 2026.
Where Ubigi wins. 3GB, 10GB in either window, 25GB and 7-day unlimited, all by clear margins, all on two named networks. That is most of the table and we are not going to talk around it.
Where the brands we sell genuinely win. At exactly 5GB for a week, Airalo's $10.00 sits in a gap Ubigi does not fill: Ubigi's choices are 3GB for $7 or 10GB for $12, so a 5GB user either goes short or pays $2 more for capacity they will not use. Airalo also has the more polished app, the largest body of English troubleshooting of any eSIM, and runs a single primary network, SK Telecom, Opensignal's best in Korea, so you always know exactly what you are on. Saily prints a 5GB daily cap and holds a 4.7 across 30,662 reviews, a support record Ubigi's 4.1 does not match. GigSky gives away 100MB, which nobody else does, and it is the one to install as a spare before flying to Jeju's counterless airport. Yesim is the only 30GB.
None of those beat $14 for 10GB on SK Telecom. They are reasons, and for some trips they are the deciding ones.
Where SK Telecom and LG U+ get Ubigi place by place, from published data and traveler reports
We have not run speed tests in Korea. These rows use MSIT's official 2025 measurements, Opensignal's December 2025 report and carrier statements, applied to the two networks Ubigi actually names.
| Place | Network under Ubigi | What the data says |
|---|---|---|
| Seoul | SK Telecom or LG U+ | MSIT's big-city 5G average is 1,090 Mbps, and Opensignal gives LG U+ the best 5G Availability in Korea at 90.3 per cent, so either network Ubigi lands on is a 5G network here. Subway averages 929 Mbps; 13 of MSIT's 32 weak-5G zones are subway sections. |
| Busan | SK Telecom or LG U+ | Both carriers keep counters at Gimhae open 06:00 to 22:00, which a Ubigi profile installed at home makes irrelevant. Small-city 5G averages 996 Mbps per MSIT. |
| KTX Seoul to Busan | SK Telecom or LG U+ | 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. Having two networks does not help because the weak zones are on every carrier. Download before boarding. |
| Jeju | SK Telecom or LG U+ | SK Telecom closed its Jeju airport roaming center at the end of June 2026 and KT's closed in 2018, so there is no counter to fall back on; Ubigi must be installed before the flight. Travelers report full 4G and 5G on all carriers including Hallasan trails. |
| Seoraksan | SK Telecom preferred | Rural 5G averages 617 Mbps per MSIT. Guides give SKT the edge on peaks and note LG U+ has no 3G fallback, so drops to no-service faster in deep valleys. On a Ubigi profile that is an argument for forcing SKT in network settings before the trailhead; the edge itself is reputation, not measurement. |
| Ferry to Ulleungdo or Jeju | SK Telecom or LG U+, neither verified at sea | KT's maritime LTE reaches about 100 km offshore and KT runs LTE plus 5G on Ulleungdo, but Ubigi does not publish KT. SKT and LG U+ sea coverage is unverified, so expect a gap mid-crossing and treat any signal as a bonus. |
Two networks on one profile does not mean you pick between them by hand every time; the phone attaches to whichever the profile prefers and whichever has signal. The setup page shows where the manual network switch lives on iPhone and Android.
Buying and activating Ubigi for Korea without a link from us
- Go to cellulardata.ubigi.com yourself and pick South Korea. We are not linking it and we earn nothing if you buy. Confirm the store shows USD; the prices on this page are what Ubigi's own plan pages showed in USD on September 7, 2026.
- Pick the window first, then the size. Ubigi's 10GB is $12 for 7 days or $14 for 30. If the trip is nine days, the 30-day plan is the one; the 7-day plan does not stretch.
- Install before you fly. The validity starts on first connection in Korea, and if Jeju is on the itinerary there is no longer a counter at the airport to help you.
- On landing at Incheon: Ubigi line on for data, US line on for calls and texts with data roaming off. The phone will show SKT or LG U+ in Latin letters. If the mountains are on your route, force SKT in manual network selection before you leave the city. Full setup and fixes.
Buy Ubigi for Korea if, buy something we sell if plainly
Buy Ubigi if
- You need 10GB. $14 for 30 days or $12 for 7 is not close to anything we link.
- You need 20 to 25GB. $25 for 25GB beats every 20GB we sell by at least $2.96 and adds 5GB.
- You want two named networks, SK Telecom and LG U+, from a brand whose parent is an operator.
- You want a week of heavy use with a printed 25GB allowance instead of a daily cap and a footnote.
Buy something we sell if
- You need exactly 5GB for a week. Airalo's $10.00 fills a gap Ubigi leaves between $7 for 3GB and $12 for 10GB.
- You want a free spare line before Jeju. Only GigSky gives away 100MB.
- You want the strongest support record. Saily's 4.7 across 30,662 is the best on the site; Ubigi's is 4.1.
- You need 30GB. Only Yesim sells it, at $35.04.
Ubigi South Korea questions short answers
Is Ubigi the best eSIM for South Korea?
On price at 10GB and 25GB, and on network disclosure, yes: $14 for 10GB on SK Telecom and LG U+ beats everything we can link. It has no 5GB plan, no free trial, and a 4.1 Trustpilot score across 45,280 reviews, under Saily's 4.7. We earn nothing from Ubigi and say all of this anyway.
Is Airalo or Ubigi better for Korea?
Ubigi at 10GB ($14 against $19 for 30 days) and 25GB ($25 against Airalo's 20GB at $30). Airalo at exactly 5GB for a week ($10, a size Ubigi does not sell), on app polish, and on knowing you are on one named network, SK Telecom, Opensignal's best in Korea. Both publish their networks, which puts them ahead of GigSky, Saily and Yesim on disclosure. The Airalo review is here.
Which network does Ubigi use in South Korea?
SK Telecom and LG U+, per Ubigi's Korea page, with 3G, 4G and 5G. SK Telecom is Opensignal's Best Network in Korea as of December 2025. Ubigi does not list KT, which is the carrier with verified maritime LTE reaching about 100 km offshore, so ferries are the one place the pairing has a visible gap.
How much is Ubigi for Korea?
1GB $3, 3GB $7, 10GB $12 for 7 days or $14 for 30, 25GB $25, and unlimited at $25 for 7 days (25GB full speed then 2 Mbps), $34 for 15 and $49 for 30 (60GB then 2 Mbps), all in USD from Ubigi's own pages, checked September 7, 2026. The store is cellulardata.ubigi.com; we do not link it.
Is Ubigi unlimited really unlimited in Korea?
No, and Ubigi prints why: the 7-day plan is 25GB at full speed then 2 Mbps for the rest of the week, and the 30-day plan is 60GB then 2 Mbps. Those are totals, not daily caps, which suits uneven trips better than Airalo's 3GB a day. For genuinely uncapped data, the Korean carriers sell it: LG U+ at about $20 for 5 days, SK Telecom via krsim at $20.70 for 7, both with passport registration after landing.
Why does this site review a Korea eSIM it does not sell?
Because Ubigi is the cheapest 10GB in every table on this site and leaving it out would make those tables a lie by omission. We are paid by Airalo, GigSky, Saily and Yesim; we are paid nothing by Ubigi, Nomad, Holafly or the Korean carriers, and all of them appear here with the reason written beside them. The full disclosure is here.
Want a named network and a link we earn from?
Airalo shows SK Telecom on its Korea page and is the only brand we can link that names a network. Its 5GB for 7 days is $10, a size Ubigi does not sell; its 10GB is $19 for 30 days, which is $5 more than Ubigi's. We earn 12 per cent if you buy it. Ubigi is cheaper at 10GB and 25GB and we are not going to pretend otherwise.
See Airalo Korea plansSources & freshness: Ubigi plan prices and fair-use totals from Ubigi's own Korea plan pages in USD on September 7, 2026; the 15-day unlimited allowance was not fetched and is marked as such. Networks from the same page. Transatel and NTT Group ownership is public corporate record. Trustpilot 4.1 across 45,280, checked September 7, 2026. Speed figures: MSIT 2025 communications quality evaluation (korea.kr, December 2025) and Opensignal South Korea, December 2025. KT maritime LTE: ZDNet Korea and Daum reporting, 2021 and May 2026. Jeju counter closures: Newsway, May 2026. We have no affiliate relationship with Ubigi, earn nothing if you buy it, and have not run our own speed tests in Korea. How we test.