Japan and South Korea on one trip: one eSIM or two?
Tokyo and Kyoto, then a short flight or the ferry to Busan and the train to Seoul. Japan and South Korea pair well on one trip, and the only question for your phone is whether one eSIM should cover both countries or each should get its own.
What do the options cost?
Our plans for 30 days, in US dollars:
| Plan | 5GB | 10GB |
|---|---|---|
| Japan only | US$7.80 | US$12.10 |
| Korea only | US$7.80 | US$12.10 |
| Asia | US$10.90 | US$18.20 |
The Asia row is our lowest priced Asia list, which currently covers both countries, plus Taiwan, Hong Kong, Macao and most of Southeast Asia, but not mainland China or Singapore. RoamMore wrote this page and sells these plans; every price comes from our live catalogue and changes when it does.
Two country plans: usually the lower price
For the same total data, a plan for each country usually costs less than one Asia plan, because Japan and South Korea are two of our lowest priced countries. Each plan is sized for its own leg, so a week in Japan and a week in Korea can be a 10GB plan and a 5GB plan rather than one plan with room for both.
The cost is a little admin: two installs instead of one, and one switch of your mobile data line when you arrive in the second country.
One Asia plan: the simplest setup
One Asia plan covers both countries, so you install once and one data balance follows you. It suits you if:
- you are not sure how your data will split between the two countries;
- your trip adds Taiwan, Hong Kong or Southeast Asia;
- you would rather not touch your phone's settings mid trip.
Check the coverage list before you buy: not every Asia plan includes both countries, and the plan finder only offers plans that cover every stop you add. The lists, with the network in each country, are on our Asia eSIM page.
Switching between two eSIMs
- Install both eSIMs at home, on wifi, a day or two before you fly.
- When you land in Japan, set the Japan line as the line for mobile data and turn on Data Roaming for it.
- When you reach Korea, choose the Korea line for mobile data instead.
- Keep your home line on for calls and texts if you want them, with its Data Roaming off.
Our landing day checklist walks through each step on iPhone and Android.
Flights and the ferry between them
Most people fly between Japan and Korea, and your eSIM simply waits on the plane. The ferry between Fukuoka and Busan keeps signal near the ports, but out at sea there is none on any eSIM, so download your tickets and maps before you board.
Where your data comes out
Some plans route your data through another country, which is why a website can think you are in Hong Kong while you are in Tokyo. Each plan row on our destination pages shows where its data comes out, and our guide to where your eSIM internet comes out explains when it matters.
How much data for Japan and Korea?
Two weeks of Standard use (maps, social media, photos and video calls) is about 14GB. Trains, maps and translation apps add up fast in both countries. Our cost and data guide has the full table, and our guides to the best eSIM for Japan and the best eSIM for South Korea compare brands country by country.
Prices for popular trips
Cheapest plan with 1GB or more, in US dollars from our catalogue, updated 30 Oct 2026.
Questions travellers ask
Can one eSIM cover Japan and South Korea?
Yes. Several of our Asia plans cover both countries, along with Taiwan, Hong Kong and much of Southeast Asia. Our South East Asia plan does not include either.
Is it cheaper to buy one eSIM for each country?
Usually, for the same total data. Japan and South Korea are two of our lowest priced countries, so a plan for each tends to cost less than one Asia plan with the same amount of data. One Asia plan is simpler, because you install once and one balance follows you.
When should I install the second eSIM?
Install both before you fly, while you have wifi. Most of our plans start when you first connect in that country, and the plan page says so if one starts as soon as it is installed. When you cross, switch the line your phone uses for mobile data.
Will my eSIM work on the Busan to Fukuoka ferry?
Near the ports your phone stays on land networks. In open sea there is no signal on any eSIM, so download tickets and maps before you board.
Do I get a Japanese or Korean phone number?
No. Our plans are data only. Calls and messages through apps such as WhatsApp work as normal, and your home number can stay on for calls and texts.