eSIM for Japan, which plan and what it costs
A data-only eSIM for Japan adds a second line to your phone for internet while your existing number stays active for calls and two-factor codes. Install the profile before you fly, activate it on landing. The choice that matters is which Japanese network the plan runs on, because that decides coverage outside the cities.
How much data you actually need
Most travellers overbuy. Maps, messaging, transit apps and a normal amount of browsing come to roughly half a gigabyte a day. Streaming video or uploading photo albums over mobile is what turns that into two or three. A ten-day trip on ordinary use lands near five gigabytes, and an unlimited plan only pays for itself if you know you are the second kind of traveller.
We are not publishing plan prices on this page yet. Every comparison we could find is written by a company selling one of the plans it ranks, and we are not willing to add a fourteenth one without measuring it ourselves. When we publish prices they will carry the date we checked them, like every other number on this site.
The question that actually decides coverage
An eSIM does not have its own network. It rents capacity from a Japanese carrier, and which one it rents from is what determines whether you have a signal in a valley in Nagano.
| Network | Where it is strongest | Worth knowing |
|---|---|---|
| NTT Docomo | Broadest rural, mountain and Hokkaido coverage | The safe default if your trip leaves the main cities |
| SoftBank | Cities and the Tokaido corridor | Common on cheaper short-trip plans |
| KDDI (au) | Cities, strong along main rail lines | Often paired with SoftBank on multi-network plans |
| Rakuten | Urban centres | Thinnest of the four outside cities |
If a listing does not tell you which network it runs on, that omission is itself information. The plans confident about their coverage say so in the first line.
Setting it up without breaking anything
- Check the phone has an EID by dialling
*#06#, and confirm it is carrier-unlocked. These are two separate things. - Buy and install the eSIM profile while you still have internet at home. Installation needs a connection; activation does not.
- Leave your home line enabled. It carries your number and your two-factor codes.
- Set the travel eSIM as the line for mobile data, and turn off data roaming on the home line.
- On landing, enable the travel line. Most plans start their validity window at first connection, not at purchase.
Step three is the one people get wrong. Removing or disabling the home SIM to “save money” is what locks travellers out of banking apps at the worst possible moment.
eSIM, pocket wifi, or roaming
| Option | Best when | Cost against it |
|---|---|---|
| Travel eSIM | One or two people, phone-first use | Needs a compatible, unlocked phone |
| Pocket wifi | Three or more people, or laptops in daily use | A device to carry, charge and return |
| Home carrier roaming | Very short trips, or where a day pass is genuinely cheap | Usually the most expensive over a fortnight |
eSIM for Japan — questions
Does a travel eSIM change my phone number?
No. A data-only travel eSIM adds a second line for internet. Your existing number stays on your physical SIM or on your primary eSIM, and it remains the number people reach you on, provided you leave that line enabled.
Will I still get my two-factor codes?
Yes, as long as your home line is switched on and not set to data-only. SMS arrives over the home line, which is why you keep it enabled and simply set the travel eSIM as the line used for mobile data. Disabling the home line is what breaks 2FA.
Do I have to remove my physical SIM?
No, and you should not. Dual SIM is the point: the physical SIM keeps your number and your codes, the eSIM carries the data. Removing the physical SIM is the single most common way travellers lock themselves out of their own accounts.
Does my phone support eSIM?
Dial *#06# and look for an EID. If there is one, the hardware supports eSIM. The other requirement is that the phone is carrier-unlocked, which is separate and which the EID does not tell you. Check both before you buy a plan.
Should I install before departure or after landing?
Install before you fly, activate on arrival. Installation needs a working internet connection, which is exactly what you will not have at the airport in Japan. Most providers let you install the profile early and start the validity period later.
Which Japanese network does the plan actually use?
This is the question that decides coverage, and most listings bury it. Docomo has the broadest rural and mountain coverage, SoftBank and KDDI are strong in cities and along the main corridors. If a plan does not name its host network, treat that as an answer.
Will it work in rural Japan and Hokkaido?
In towns and along rail lines, generally yes. In the mountains, on hiking trails and in parts of Hokkaido, coverage depends entirely on the host network, and this is where Docomo-backed plans pull ahead. Do not assume city performance transfers.
Can I use tethering?
Some plans allow it, some block it, and a few permit it only up to a cap. If you plan to share the connection with a laptop or a travelling companion, check the tethering line in the plan terms before buying, because it is rarely mentioned in the headline.