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 2026 that is only half true, and the half that is false saves you money on short, heavy trips.
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 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 10GB for 30 days is $25.00 against $19.00.
The middle of the ladder is where the sum gets close. Asialink now sells 5GB, 10GB and 20GB as well as 1GB, 3GB, 50GB and 100GB, at $4 to $9 over the Korea-only price. That premium buys the whole of Japan, so the real question is what a Japan plan of your size costs on its own.
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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 | $14.00 | +$4.00 |
| 5GB / 30 days | $11.00 | $15.00 | +$4.00 |
| 10GB / 15 days | $18.50 | $24.00 | +$5.50 |
| 10GB / 30 days | $19.00 | $25.00 | +$6.00 |
| 20GB / 15 days | $29.00 | $38.00 | +$9.00 |
| 20GB / 30 days | $30.00 | $39.00 | +$9.00 |
| 50GB / 30 days | $49.00 | $59.00 | +$10.00 |
| 50GB / 90 days | not sold | $69.00 | regional only |
| 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 Airalo's own Korea and Asia plan pages, checked 2026. Airalo geo-serves Canadian dollars to some visitors; we read the USD prices.
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. If Japan is a trip of its own, our Japan eSIM guide covers the Japan-only plans and networks.
| 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 | $25.00 Asialink 10GB / 30 days | Close. Regional wins if your Japan plan would cost more than $6. |
| 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 unlimited wins outright on short heavy trips, and the fixed buckets cost $4 to $10 more than Korea alone, which is usually less than a separate Japan plan. Two plans still win when Japan is a short, light leg you can cover cheaply. Korea prices checked 2026.
One regional eSIM or two country plans?
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. Asialink 10GB is $25.00 for 30 days; Jjang 10GB is $19.00 on SK Telecom for the Korean half alone. If a Japan plan of the size you need costs more than $6, one Asialink profile is cheaper and simpler.
Jjang publishes SK Telecom, Opensignal's Best Network in Korea for December 2025; Asialink does not name its Korean network. 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 around 10GB, Asialink 10GB is $25.00 against Airalo Jjang 10GB at $19.00 for Korea alone, so one plan wins if your Japan plan would cost more than $6. Checked 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 over Korea alone, for example $25.00 against $19.00 at 10GB, and that premium covers Japan too.
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 on 5G; Asialink's Korean network is not published on Airalo's Asia page. 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, Asialink is $25.00 against $19.00 for Korea alone; price your Japan leg before you choose.
See Airalo Asialink plansSources & freshness: Airalo Jjang and Asialink prices from Airalo's own plan pages (airalo.com/south-korea-esim and airalo.com/asia-esim) in USD, checked 2026, before promo codes. 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.