Most Japan travel eSIMs run on NTT Docomo: 47 of the 72 distinct plans covering Japan in our catalogue list Docomo, 29 list KDDI, 25 list SoftBank and 11 list Rakuten Mobile. Since 23 October 2026 our Japan-only plans use Docomo, from $3.09 for 1 GB, or KDDI on our KDDI 5G plans, from $6.49, and all of them route data through Japan. SoftBank appears only on regional plans, such as South Korea and Japan or Asia 15 Countries.
Ask which network to use in Japan and you will hear that Docomo reaches the mountains, SoftBank is fastest in Tokyo, and au (KDDI) is the most reliable. All of those have been true at some point. On a travel eSIM, though, the network comes with the plan, and it is printed on every plan page. We sorted all the plans covering Japan by the Japanese networks they name, using our catalogue on 5 October 2026. Identical listings are counted once.
- NTT Docomo: on 47 plans, including 19 of the 25 Japan-only plans.
- KDDI and SoftBank: always listed together, on 25 plans on 5 October 2026. The three Japan-only plans among them moved to Docomo on 23 October 2026, so the pair now appears on regional plans only. Separately, we added KDDI 5G plans for Japan alone on the same day.
- Rakuten Mobile: on 11 plans, always alongside Docomo, all from one provider whose plans start when installed.
- Data exit: the Docomo Japan-only plans exit in Japan; most regional plans exit in Hong Kong, Singapore or the UK.
Japan’s four mobile networks
Japan has four mobile network operators: NTT Docomo, KDDI (sold as au), SoftBank and Rakuten Mobile. Opensignal’s Japan mobile network report scores them on reliability, speed and coverage, and different operators lead different categories. Check the latest edition if a particular measure matters to you.
For a traveller, the practical question is which of them your plan can use. A roaming eSIM attaches only to the Japanese networks its provider has agreements with, and a plan that lists two networks gives the phone a fallback when one signal is weak, on a mountain road in the Japanese Alps or deep in a station concourse.
Which network each Japan plan uses
| Japanese networks listed | Plans | Examples | From |
|---|---|---|---|
| NTT Docomo only | 32 | 19 Japan-only plans; Japan 10 GB, 30 days; Europe Asia and USA | $1.99 day pass |
| KDDI and SoftBank | 25 | Asia 12 Countries; on 5 October also three Japan-only plans, which moved to Docomo on 23 October | $4.00 |
| NTT Docomo and Rakuten Mobile | 11 | South Korea and Japan 10 GB; China Korea Japan | $9.00 |
| NTT Docomo and KDDI | 4 | Best World, 174 countries | $8.20 |
See and filter every Japan plan: the Japan eSIM page lists them all, and each plan page names its networks in the Destinations and networks table.
Docomo plans: cheapest, with a Japanese IP
The Docomo Japan-only plans are the cheapest way to stay online in Japan, from 1 GB for 3 days at $3.09 and 5 GB for 7 days at $4.49 to 50 GB for 30 days at $22.99, plus day passes and unlimited plans from 1 to 30 days. Their data exits in Japan, so Japanese websites and apps see a Japanese IP address. Our Japan local eSIM page lists every one of them in a single table.
They all list hotspot as supported, as do the three IIJ plans on Docomo from 12 GB for $9.25. The trade-off is on the day passes, which give 1, 2 or 3 GB a day at high speed, then 256 kbps; the unlimited plans have no daily allowance. Our cheapest Japan eSIM guide compares every size.
SoftBank and KDDI plans
Until 22 October 2026, three Japan-only plans listed SoftBank and KDDI and routed data through Hong Kong. Since 23 October they run on Docomo with a Japanese IP: Japan 3 GB for 30 days, now $4.29, Japan Short Trip, 3 GB for 5 days, now $3.89, and Japan Unlimited for 3 days at $9.80, which no longer slows down after 3 GB a day. SoftBank and KDDI, always listed together, now appear only on regional plans, such as South Korea and Japan 10 GB at $9.00, which exits in Hong Kong, and Asia 15 Countries 10 GB at $9.80, which exits in Singapore. Their plan pages say hotspot sharing has a data limit on KDDI. For KDDI alone with a Japanese IP, our KDDI 5G plans are local au lines from $6.49 that support hotspot: the fixed plans can share all their data, and the unlimited plans up to 1 GB less than the number of days in total. They cannot be refunded once the QR code is issued.
Whether unlimited is worth it depends on your trip length; our Japan unlimited vs 30-day comparison works through it.
Does the network matter for a traveller?
- In Tokyo, Osaka and Kyoto, rarely. All four operators run 4G and 5G networks, and you will spend most of your data in the cities.
- In the countryside, two networks help. On a plan that lists two Japanese networks, the phone can switch when one signal is weak. Every plan that lists SoftBank lists KDDI too.
- The exit matters more than people expect. A Japanese IP keeps Japanese services working as they would for a resident; a Hong Kong or UK exit can change what some region-checked services show. See how a travel eSIM changes your IP address.
Pick a plan by what you need
| You want | Good fit | Network | Price |
|---|---|---|---|
| The lowest price for a week | Japan 5 GB, 7 days | NTT Docomo | $4.49 |
| Hotspot for a laptop | Japan 10 GB, 30 days | NTT Docomo | $7.00 |
| SoftBank or KDDI | Asia 15 Countries 10 GB, 30 days | KDDI, SoftBank | $9.80 |
| KDDI with a Japanese IP | Japan KDDI 12 GB, 4 days | au (KDDI), 5G | $7.39 |
| Unlimited for a few days | Japan Unlimited 7 days | NTT Docomo | $19.00 |
| Japan and Korea | South Korea and Japan 10 GB | KDDI, SoftBank | $9.00 |
Installing before you fly? All our Japan-only plans start on first data use except the three IIJ plans, which start the moment they are installed. See when an eSIM starts counting for when to install, when to switch the line on, and why a late first connection shortens day 1 on Japan-time plans.
Comparing brands, not just plans? Our best eSIM for Japan guide puts our prices next to Airalo, Ubigi and Holafly for the same trips, with networks, speed limits and hotspot rules.
Frequently asked questions
Which network is best for tourists in Japan?
Independent tests rank Japan’s four networks differently by category, so there is no single winner. On a travel eSIM, the plan decides: most of our Japan-only plans use NTT Docomo, our KDDI 5G plans use au (KDDI), and some regional plans use SoftBank and KDDI together. A plan with two networks helps most outside the big cities.
Does a Japan eSIM use Docomo or SoftBank?
It depends on the plan. On 5 October 2026, 47 of the 72 distinct plans covering Japan in our catalogue listed NTT Docomo and 25 listed SoftBank, always together with KDDI. Each plan page names its networks in the Destinations and networks table.
Can I get a Japan eSIM on au (KDDI)?
Yes. Since 23 October 2026 we sell KDDI 5G plans for Japan alone, local au lines with a Japanese IP, from $6.49 for 3 days of unlimited data at up to 10 Mbps; they cannot be refunded once the QR code is issued. KDDI also appears on regional plans, such as South Korea and Japan 10 GB, with SoftBank, for $9.00.
Is there a Japan eSIM on Rakuten Mobile?
Only alongside Docomo. Rakuten Mobile appears on 11 plans in our catalogue, all from one provider, including South Korea and Japan 10 GB at $9.00. These plans start counting days when the eSIM is installed, so install them close to departure.
Why does a Japan eSIM’s IP address matter?
Some websites and apps adjust content or access by country. The Docomo Japan-only plans exit in Japan, so you appear to be in Japan. Many regional plans exit in Hong Kong, Singapore or the UK instead. Maps, messaging and browsing work either way.
Which Japan eSIM supports hotspot?
All of them: every Japan-only plan we sell lists hotspot as supported, along with most regional plans. Our KDDI 5G plans support hotspot as well: the fixed plans can share all their data, and the unlimited plans up to 1 GB less than the number of days in total, for example 6 GB on a 7-day plan. Some regional plans that use KDDI in Japan say on their plan pages that hotspot sharing has a data limit there.
In Japan, all four networks are good enough for a traveller most of the time. Pick the plan for price, hotspot or unlimited data, and the network comes with it.
Updated 23 October 2026, when our Japan-only plans moved to Docomo and we added KDDI 5G plans; the prices quoted are from that date. Hotspot terms were last reviewed on 23 October 2026 and network counts are from 5 October 2026. All of these come from our own catalogue and product pages and change often; product pages are authoritative. Identical listings are counted once. NTT Docomo, KDDI, au, SoftBank and Rakuten Mobile are trademarks of their owners; this article is independent of them.