The regional plan, priced both ways
One eSIM for Korea and Japan?
The usual advice is that a regional plan always costs more than two country plans. For Korea and Japan, in September 2026, that is only half true, and the half that is false saves you money at exactly one trip length.
Why a Korea and Japan eSIM is a different sum from most regional plans the premium runs both ways
Regional plans are normally a convenience product with the convenience priced in. Airalo's Asialink breaks that rule at one end of its ladder and follows it at the other.
Airalo's Korea eSIM is called Jjang and its Japan eSIM is called Moshi Moshi; both are country plans. Asialink is the regional one, covering Korea, Japan and most of Asia on a single profile. On September 7, 2026 the Asialink unlimited ladder undercuts Jjang at three, five and seven days, matches it at ten and fifteen, and only becomes dearer at thirty. Its fixed buckets, by contrast, carry the usual regional markup: 3GB for seven days is $9.50 against Jjang's $9.00.
And the gap in the middle is the real story. Asialink sells 1GB, 3GB, 50GB and 100GB. There is no 5GB and no 10GB, which are the sizes most two-week visitors actually need. For those trips the regional plan is not expensive, it is absent, and two country plans are the only option.
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Airalo Asialink against Airalo Jjang, size for size the same company, two prices
| Plan | Jjang, Korea only | Asialink, Korea + Japan + Asia | Regional premium |
|---|---|---|---|
| 1GB / 3 days | $4.00 | $4.00 | $0 |
| 3GB / 3 days | $8.00 | $9.00 | +$1.00 |
| 3GB / 7 days | $9.00 | $9.50 | +$0.50 |
| 5GB / 7 days | $10.00 | not sold | two plans |
| 10GB / 30 days | $19.00 | not sold | two plans |
| 20GB / 15 days | $29.00 | not sold | two plans |
| 50GB / 30 days | $49.00 | $59.00 | +$10.00 |
| 100GB / 180 days | not sold | $89.00 | regional only |
| Unlimited, 3 days | $12.00 | $11.50 | −$0.50 |
| Unlimited, 5 days | $20.00 | $19.00 | −$1.00 |
| Unlimited, 7 days | $29.00 | $26.00 | −$3.00 |
| Unlimited, 10 days | $35.00 | $35.00 | $0 |
| Unlimited, 15 days | $49.00 | $49.00 | $0 |
| Unlimited, 30 days | $69.00 | $73.50 | +$4.50 |
Both unlimited ladders carry Airalo's published 3GB-a-day cap, then 1 Mbps. So at three, five and seven days Asialink gives you the same Korean allowance for less money and adds Japan. There is no version of that trip where the Korea-only plan makes sense. The other unlimited caps are here.
Prices in USD from esimdb and Airalo's plan pages on September 7, 2026; the Asialink 50GB and 100GB figures were pulled on September 4, 2026. Airalo geo-serves Canadian dollars to some visitors on its own site; the checkout is USD.
A week across Seoul and Tokyo with video and hotspot: Asialink unlimited at $26.00 is the cheapest way to do it that we know of, from the same brand you would have bought for Korea alone.
See Airalo Asialink Read the Airalo Korea reviewWhat each Korea and Japan trip actually costs two plans against one
We price the Korea leg, because that is what this site checks. For the Japan leg we say "a Japan country plan" and give no number: a price we have not verified this month is a price we do not print.
| Trip | Two country plans | One Asialink plan | Verdict |
|---|---|---|---|
| 7 days, heavy use in both, video and hotspot | $29.00 Jjang unlimited + a Japan country plan | $26.00 Asialink unlimited | Regional, before you have even added Japan. |
| 7 days, light use, ≈3GB total across both | $9.00 Jjang 3GB + a Japan country plan | $9.50 Asialink 3GB | Regional, if 3GB really covers both legs. Fifty cents buys the second country. |
| 10 to 14 days, normal use, ≈10GB total | $19.00 Jjang 10GB + a Japan country plan | $59.00 Asialink 50GB, the smallest bucket above 3GB | Two plans. Asialink has nothing between 3GB and 50GB. |
| 10 to 15 days, heavy use in both | $35.00 or $49.00 Jjang unlimited + a Japan country plan | $35.00 or $49.00 Asialink unlimited, identical price | Regional. Same price as Korea alone, Japan free. |
| 30 days, heavy use, ≈45GB total | $49.00 Jjang 50GB + a Japan country plan | $59.00 Asialink 50GB | Regional, unless a Japan plan of the size you need costs under $10. |
| 30 days, unlimited in both | $69.00 Jjang unlimited + a Japan country plan | $73.50 Asialink unlimited | Regional on the same logic: $4.50 for the whole of Japan. |
| Two Asia trips within six months | four purchases | $89.00 Asialink 100GB / 180 days | Regional, and nothing else on this site has that validity. |
The pattern: Asialink wins wherever it sells the size you need, and loses only by not existing in the 5 to 20GB range. That range is most two-week holidays, which is why the two-plan advice survives. Korea prices checked September 7, 2026.
When to buy the regional Korea and Japan eSIM and when to buy two six honest cases
Video every evening, a hotspot for the laptop, no interest in counting gigabytes. Asialink unlimited at $26.00 for seven days is cheaper than the Korea-only version at $29.00 and covers the Japan leg too. Same 3GB-a-day cap on both.
Three gigabytes across seven days is enough for Naver Map, KakaoTalk, Papago and their Japanese equivalents if photos wait for wifi. Asialink's 3GB for seven days is $9.50; the Korea-only version is $9.00 and then you still need Japan.
Asialink's 100GB over 180 days at $89.00 is the only long-validity product on this site. Two trips to Asia on one profile with no repurchase, at 89 cents a gigabyte, the lowest rate we know of.
The most common Korea and Japan trip and the one where Asialink has nothing to sell you: its ladder skips from 3GB to 50GB. Jjang 10GB at $19.00 on SK Telecom for the Korean half, plus a Japan country plan of similar size, is the whole answer.
Only Jjang publishes SK Telecom, Opensignal's Best Network in Korea for December 2025. If the KTX or a rural leg is why you care, buy Korea deliberately and let the Japan plan be whatever it is. In Korean cities, honestly, it will not matter.
Ten working days in Seoul and a weekend in Osaka: Jjang unlimited at $35.00 for ten days plus a tiny Japan country plan. A regional unlimited plan charges the heavy rate for both legs, and here the ten-day Asialink is the same $35.00 anyway, so this is a coin flip. Take Jjang if you want the network named.
How to run a Korea eSIM and a Japan eSIM on one phone five taps at the gate
- Install both profiles at home, on wifi, before either flight. Recent iPhones hold eight or more eSIM profiles and most current Android handsets several. Neither plan starts counting until it connects in its own country.
- Label them by country when the phone asks: "Korea" and "Japan", not "Travel" and "Travel 2". You will be switching them in a boarding queue at Incheon.
- Enable only the country you are in. A disabled profile costs nothing. On the Korea leg, the Korea line is on and set as the data line; the Japan line is off.
- Swap at the gate or on the plane. iPhone: Settings, Cellular, turn Korea off, turn Japan on, set Cellular Data to Japan. Android: Settings, SIMs, the same two toggles. Fifteen seconds.
- Keep your home line on for calls with data roaming off on both legs. That is what stops the daily roaming charge while keeping your own number alive for bank codes. The full setup page and the symptom-to-fix table.
Korea and Japan eSIM questions short answers
What is the best eSIM for Korea and Japan?
For a heavy week, Airalo Asialink unlimited at $26.00: cheaper than Airalo's Korea-only unlimited at $29.00 and it includes Japan. For a normal two-week trip needing 5 to 20GB, Asialink sells no plan that size, so buy Airalo Jjang 10GB at $19.00 for Korea plus a Japan country plan. Checked September 7, 2026.
Does a Korea eSIM work in Japan?
No. Airalo's Jjang, and every other Korea country plan on this site, stops at the Korean border. For Japan you need a Japan country plan, a regional plan such as Airalo Asialink that lists both countries, or a second profile installed before you leave and switched on when you land.
Is Airalo Asialink cheaper than two country plans?
Sometimes, which is unusual for a regional plan. Its unlimited plans undercut Airalo's Korea-only unlimited at three, five and seven days and match it at ten and fifteen. Its fixed buckets carry a premium of 50 cents to $10. And it sells nothing between 3GB and 50GB, so mid-size trips have to buy two plans regardless.
Can I have a Korea eSIM and a Japan eSIM on the same phone?
Yes. Recent iPhones store eight or more profiles and run two lines at once; current Android handsets hold several. Install both at home on wifi, label them by country, enable one at a time. Neither begins its validity until it first connects in its own country.
Which network does Asialink use in Korea?
Airalo does not say. Its Korea-only Jjang plan lists SK Telecom as the primary network; Asialink's Korean network is not published, and the same is true of every regional plan in both countries. In Korea all three carriers reach the places visitors go, so this matters mainly on the KTX and in deep mountain valleys.
A heavy week in both? $26.00, Japan included
Airalo Asialink's seven-day unlimited costs three dollars less than the same company's Korea-only plan, with the same published 3GB-a-day cap. For a normal 10GB fortnight, buy Jjang for Korea and a Japan plan separately, because the regional ladder skips your size entirely.
See Airalo Asialink plansSources & freshness: Airalo Jjang and Asialink prices from esimdb and Airalo's plan pages on September 7, 2026, in USD, before promo codes; Asialink's 50GB and 100GB figures were pulled on September 4, 2026. Japan country-plan prices are deliberately not quoted: this site checks Korea, and we do not print numbers we have not verified this month. Network claims are Airalo's published statements, not our tests. Opensignal's Korea award is from its December 2025 report. How we test.