Unlimited Japan eSIM Data | Docomo, au & SoftBank
Roami
Roami is a global eSIM carrier focused on travel connectivity. This guide is compiled from network data, official carrier and manufacturer documentation, and traveler inquiries.
📑 Table of Contents
Pick a network, not a brand: which carrier should your Japan eSIM connect to? Japan’s four national networks are not interchangeable. On Ookla’s 2H 2024 Japan report, Rakuten Mobile was the most consistent network at 89.9%, SoftBank offered the best video and gaming experiences, NTT Docomo led on 5G availability at 43%, and au balanced city and rural reach. Which one is best depends on where you are going, because the best eSIM carrier for Japan is a routing decision, not a brand decision. After guiding enough travelers through their first Japan eSIM, we know the usual confusion points; the sections below address them one by one.
Some phones cannot take an eSIM at all, and plenty of people have never seen a profile install. Both gaps are covered elsewhere — the eSIM compatibility quiz and the activation explainer — so this page can stay on the networks.
If you read nothing else: Staying in Tokyo, Osaka or Kyoto? Rakuten Mobile runs the fastest 5G in the country at 151.16 Mbps and the most consistent network at 89.9%. Streaming a lot of video or gaming? SoftBank wins on video score (75.91) and gaming score (80.94). Heading into rural Tohoku, Hokkaido or the mountains? NTT Docomo holds signal where the others fade, thanks to the best 5G availability at 43%. Want a carrier eSIM as a visitor? Only au sells one walk-up, through its povo brand at Lawson. Or skip the paperwork: free eSIM trial tests the networks at no cost; apply code WEB20 for 20% off Japan prepaid eSIM plans.
Which networks can your eSIM use in Japan?
Docomo, au, SoftBank and Rakuten, scored for visitors
| NTT Docomo | au (KDDI) | SoftBank | Rakuten Mobile | |
|---|---|---|---|---|
| Prepaid eSIM for short-stay visitors | No — direct eSIM needs a Japanese address and residence card | Yes — povo sells a tourist eSIM at Lawson | No — LINEMO needs a residence card | No — eKYC needs a residence card and Japanese card |
| Best measured strength | Widest coverage, best 5G availability at 43% | Balanced city and rural reach | Best video (75.91) and gaming (80.94) | Fastest 5G (151.16 Mbps), most consistent (89.9%) |
| Cheapest direct tourist plan | None direct; Docomo network via IIJ from ¥2,480 | povo 3 GB / 7 days at ¥2,200 | None direct; SoftBank network via travel eSIM | None direct; resident plan from ¥1,078/mo |
| Ease for a visitor | ★ — residents only | ★★★ — buy at Lawson with cash and passport | ★ — residents only | ★ — residents only |
Three of the four doors are shut. Docomo, SoftBank and Rakuten all route their own eSIM through resident contracts that demand a residence card and a Japanese payment method. Only au opens a door for tourists, through its povo brand at Lawson convenience stores. Everyone else reaches these networks through a travel eSIM riding on top of them.
Cheapest data in Japan, compared
Japan’s fourth tier is where visitors actually find usable prepaid eSIMs, either from a carrier flanker or from a budget brand that leases network capacity.
| Brand | Parent network | Tourist eSIM? | Who it suits |
|---|---|---|---|
| IIJmio Japan Travel SIM | NTT Docomo | Yes — at FamilyMart from 25 November 2025 | Visitors who want Docomo coverage without a contract |
| povo | au (KDDI) | Yes — at Lawson | Short stays, cash buyers, au network fans |
| LINEMO | SoftBank | No — needs a residence card | Residents on a budget |
| ahamo | NTT Docomo | No — needs Japanese ID | Residents wanting 20 GB |
| UQ mobile | au (KDDI) | No — needs Japanese ID | Residents in au areas |
| Y!mobile | SoftBank | No — needs Japanese ID | Residents in SoftBank areas |
Two cautions. First, budget brands that lease Docomo or au capacity are still tied to one network, so they show the same gaps as the parent the moment you leave the city. Second, from 1 April 2026 every one of these brands must scan your passport or residence card before activation, so the old “anonymous travel SIM” is gone.
Can you buy a Japan eSIM from Docomo?
| Direct from a Japanese carrier | Travel eSIM on a Japanese network | |
|---|---|---|
| What you need | Passport and, for most, a residence card; Japanese payment method | A compatible, unlocked phone |
| How the profile arrives | In store, app, or QR after ID checks | QR code or app install right after checkout |
| Typical cost | povo 3 GB / 7 days at ¥2,200; resident plans ¥990 to 2,970/mo | One upfront price, no residence card |
| Network access | One carrier, or povo on au | Automatic switching across Docomo, au, SoftBank, Rakuten |
| ID rule from April 2026 | Passport scanned at the point of sale | Passport uploaded at checkout |
| Best for | Long stays with a residence card | Trips of days to weeks, online on landing |
For a two-week trip the numbers do not favour a local plan. A carrier contract is built for residents who want a Japanese number and monthly billing; a travel eSIM buys data at wholesale and lets the device move between networks. Where the carrier wins is longevity and voice, a real local number and unlimited domestic calling, which only matters once you live in Japan.
💡 A multi-network eSIM profile is the practical middle path: Roami’s Japan eSIM keeps the convenience of instant delivery, switches automatically between Docomo, au, SoftBank and Rakuten, and still lands you on Rakuten in Tokyo and Docomo in the mountains without buying twice.
Will my phone work on Japanese networks?
Three things decide whether your phone works on a Japanese carrier: its bands, its lock status, and a short list of device-specific quirks. All three are covered below.
Does my model qualify for Japan eSIM service?
Japanese carriers build their 5G on specific bands, and the split matters more than in most countries. Rakuten Mobile, au and SoftBank all share the global mid-band n77, so almost any foreign 5G phone connects there. NTT Docomo adds its own n79 layer and leans on LTE Band 19 at 800 MHz for low-band coverage, and many North American and European handsets ship without those two. Those phones still work on Docomo, but they fall back to Bands 1 and 3 and lose signal in rural areas, mountain tunnels and the Shinkansen.
The Japanese band list looks intimidating and is mostly not worth learning. The safe bet is to match your exact model, the model number rather than the shop name, against the eSIM compatibility list. Want the theory before the practice? The explainer on what your phone does when it loads an eSIM profile covers the load sequence.
Docomo vs au: which is better in Japan?
A locked phone is the most common reason a Japan eSIM install simply fails, and Japan has unusually clear rules here.
Under guidelines from the Ministry of Internal Affairs and Communications that took effect in September 2019, Japanese carriers must offer SIM-lock removal, and the process is free when done through the carrier’s online or phone channel. Phones sold since May 2015 are unlockable once any mandatory lock-in period, commonly around 100 to 180 days, has passed. MIC names eSIM on its own travel advice as a way to avoid roaming charges.
How to check: iPhone → Settings → General → About → Carrier Lock. Where the field says “No SIM restrictions”, the phone is free to take a profile. If the field shows “SIM locked”, no outside profile will load until the handset is freed.
Fix it: the operator that sold the handset is the one to ask for an unlock. Devices that are paid off are normally cleared within hours, and there is no fee through the carrier’s self-serve channel. Only then try installing your eSIM.
If you bought a phone from a US or European carrier, assume it may be locked and check before you fly. Full detail: MIC — travelling with your device.
Handset compatibility in Japan
| Device | Symptom | What to do |
|---|---|---|
| Carrier-locked phone, for example a US carrier lock | eSIM install fails entirely | Unlock through the original carrier first, then retry |
| Foreign phone missing Band 19 | Docomo drops to Bands 1 and 3 only; dead zones on trains and in mountains | Use SoftBank or au, or a multi-network eSIM |
| Phone without n77 or n78 | 4G only, no 5G | Expected; 4G is still fast in Japan |
| Mainland-China iPhone | No Add eSIM option at all, hardware disabled | Not fixable; use a different device |
| Dual-SIM users | eSIM installed but no data | Set the eSIM as the mobile data line |
Beyond those cases it is the model, not the network, that decides. Drop your exact handset into the device compatibility checker before you pay for any plan.
What Japan data plans cost and where to buy them
Four routes exist, and they differ more in paperwork than in price: au through povo for a true tourist eSIM, Docomo and SoftBank through resident brands, and Rakuten as a resident contract. Each route, step by step.
Sales channels for Japan eSIMs
Docomo’s own consumer eSIM is for domestic users: it wants a Japanese address and a residence card, and it rides on plans like ahamo, Gigaho or Gigalight. International visitors are pointed at the Docomo network through budget brands instead.
Reaching Docomo as a visitor, step by step:
- The cleanest tourist route is IIJmio Japan Travel SIM, which runs on Docomo’s 4G and 3G network. From 25 November 2025 it is sold at FamilyMart multifunction copiers nationwide.
- Pick a plan on the copier, pay at the register, and receive a slip with an entry code.
- Register on the dedicated website, enter the code, and download the eSIM profile over Wi-Fi.
- No residence card, no Japanese credit card, and the plans are data-only with no contract.
Docomo explicitly serves visitors this way rather than through its own app, because its own eSIM assumes a resident identity. Check your model before buying.
Japan price check: local vs travel eSIM
au is the one national carrier that sells a tourist eSIM directly. Its povo brand launched “povo2.0 Japan SIM” at roughly 14,600 Lawson stores from 1 July 2025, and it is built for exactly this.
povo tourist eSIM, step by step:
- At a Lawson copier or register, choose a plan and pay in cash.
- Scan the QR code on the slip and open the dedicated website.
- Enter the PIN from the SIM card and add the eSIM profile to your device.
- You connect to au’s network in about three minutes, no residence card, no Japanese card.
| Carrier or brand | Plan | Data and validity | Price (JPY) | How to buy |
|---|---|---|---|---|
| au via povo | 3 GB / 7 days | 3 GB, 7 days | ¥2,200 | Lawson, cash |
| au via povo | 10 GB / 30 days | 10 GB, 30 days | ¥3,280 | Lawson, cash |
| au via povo | 25 GB / 30 days | 25 GB, 30 days | ¥4,580 | Lawson, cash |
| au via povo | Unlimited / 7 days | unlimited, 7 days | ¥4,500 | Lawson, cash |
| Docomo via IIJ | 3 GB / 30 days | 3 GB, 30 days | ¥2,480 | FamilyMart |
| Docomo via IIJ | 10 GB / 30 days | 10 GB, 30 days | ¥3,280 | FamilyMart |
| Docomo via IIJ | 55 GB / 30 days | 55 GB, 30 days | ¥5,780 | FamilyMart |
| Rakuten, resident | SAIKYO up to 3 GB | monthly | ¥1,078/mo | App, residence card |
| SoftBank via LINEMO, resident | 3 GB | monthly | ¥990/mo | App, residence card |
| SoftBank via LINEMO, resident | 20 GB | monthly | ¥2,970/mo | App, residence card |
povo notes that speed may be limited during network congestion, which is the one catch on a busy festival day. If you only want au coverage as a visitor, povo is the route; a travel eSIM is the alternative that also reaches the other three networks.
Does SoftBank sell a tourist eSIM for visitors?
SoftBank does not sell a direct prepaid eSIM to short-stay visitors. Its online budget brand LINEMO requires a residence card and a Japanese payment method, and its eSIM tiers are limited to permanent or special permanent residents. SoftBank’s own prepaid history is physical SIM and its Free Wi-Fi Passport, not a tourist eSIM.
For SoftBank network data as a visitor, the practical paths are a travel eSIM that rides on SoftBank, or a budget brand that leases its capacity. SoftBank remains worth targeting because Ookla rated it best for video and gaming in 2H 2024, which matters if you stream or play on the move.
What Japan eSIM plans cost
Rakuten Mobile is the fastest and most consistent network in Ookla’s 2H 2024 Japan data, but it is built for residents. Its eKYC wants a residence card or special permanent resident certificate, a Japanese address, and a Japanese-issued credit card or bank account. Overseas cards are rejected.
Rakuten’s SAIKYO Plan is genuinely cheap, about ¥1,078/mo up to 3 GB, ¥2,178/mo from 3 to 20 GB, and ¥3,278/mo above 20 GB with an unlimited tier, but the eligibility bar is the point. An ordinary tourist on a 90-day stay cannot clear it, so Rakuten reaches visitors through travel eSIM brands that lease its network rather than through Rakuten itself.
Docomo eSIM plans for visitors
- Passport — scanned or photographed; required at every checkout from 1 April 2026
- Residence card — only if you are a resident signing a carrier contract
- IMEI — dial
*#06# - EID — also from the
*#06#screen; the eSIM’s own identifier - Unlocked phone — look for No SIM restrictions in the Carrier Lock entry
- Wi-Fi — install the profile before you fly, not at the airport
- A card that works in Japan — some carrier checkouts reject foreign billing addresses
Plans and current tiers live on our Japan eSIM page. Install at home so the profile connects the moment you land, and if you plan to tether a laptop, check the plan’s hotspot policy before buying.
Which Japanese network is fastest for your trip?
Two things decide the answer here: the speed each carrier delivers where you will be, and the kind of trip you are on. The carrier scores below settle the speed question, and the trip table settles the second.
How consistent are Rakuten Mobile, SoftBank, au and Docomo?
All figures below come from Ookla’s Speedtest Connectivity Report for Japan, collection period July to December 2024, and the carrier-level consistency scores are the figures supplied for this guide.
| Carrier | Consistency Score |
|---|---|
| Rakuten Mobile | 89.9 |
| SoftBank | 85.7 |
| NTT Docomo | 84.9 |
| au | 82.4 |
Source: Ookla Speedtest Connectivity Report — Japan, July to December 2024, the per-carrier report. Consistency Score reflects the share of samples meeting 5 Mbps down and 1 Mbps up.
Where the report publishes further carrier detail, the picture is consistent with the table above. Rakuten Mobile was the fastest 5G network with a median 5G download of 151.16 Mbps and a 5G Speed Score of 139.48. NTT Docomo placed second on 5G download at 119.75 Mbps and led 5G availability at 43%. au recorded 115.24 Mbps on median 5G download. SoftBank posted the best video streaming score at 75.91 and the best gaming score at 80.94. Every number traces to the same Ookla report.
| Metric | Rakuten Mobile | au | NTT Docomo | SoftBank |
|---|---|---|---|---|
| Median 5G download | 151.16 Mbps | 115.24 Mbps | 119.75 Mbps | not published |
| 5G Speed Score | 139.48 | not published | not published | 104.96 |
| Best video streaming score | not published | not published | not published | 75.91 |
| Best gaming score | not published | not published | not published | 80.94 |
| Best 5G availability | not published | not published | 43% | not published |
| Most consistent network | 89.9% | not published | not published | not published |
For context on the country as a whole, Ookla’s Speedtest Global Index puts Japan’s median mobile download around 66 Mbps, well below the global median, because Japan’s strength is density and reliability rather than raw speed. Cable.co.uk prices 1 GB of Japanese mobile data at roughly USD 3.48, ranked 201st of 237 markets, so local data is mid-priced rather than cheap.
Best Japan carrier by travel plan
| Your trip | Best carrier | Why | Watch out for |
|---|---|---|---|
| City break, Tokyo, Osaka, Kyoto | Rakuten Mobile | Fastest 5G at 151.16 Mbps and most consistent at 89.9% | Festival crowds throttle at peak times |
| Video streaming, gaming | SoftBank | Best video (75.91) and gaming (80.94) | Upload is not the fastest |
| Rural Tohoku, Hokkaido, mountains | NTT Docomo | Widest coverage, best 5G availability at 43% | Your phone needs Band 19 for low-band |
| Balanced city and regional | au | Strong nationwide on the povo tourist eSIM | Needs B18 or B26 for deep rural |
| Business travel and calls | Docomo or SoftBank | Reliable and broad | Travel eSIMs are data-only, no local number |
| Multi-region road trip | A multi-network eSIM | Switches as you move | Single-carrier plans show gaps between regions |
Regional coverage: from Hokkaido to Okinawa
Japanese coverage tracks population density — dense in the metros, thinning fast along mountain roads and largely absent on the outer islands. Route by route:
| Region | Reality on the ground |
|---|---|
| Tokyo and Kanto | All four strong; Rakuten fastest 5G; Osaka recorded the fastest median mobile download in Japan at 63.12 Mbps (Ookla) |
| Osaka and Kansai | Dense-city coverage is excellent; Dotonbori and Universal Studios Japan stay fast even when busy |
| Hokkaido | Docomo strongest in rural and ski areas; Rakuten and SoftBank thin off the main routes |
| Tohoku | Docomo leads; the others are sparse outside the prefectural capitals |
| Kyushu and Shikoku | City coverage is fine; rural mountain roads are patchy on every carrier |
| Okinawa | Docomo and SoftBank are good on the main island; the outer islands are thin |
| Mountain areas | Docomo’s Band 19 holds signal; Rakuten is limited away from cities |
| Shinkansen | Docomo is most consistent in tunnels; always download offline maps first |
Crossing a border? We publish the same sourced breakdown for South Korea eSIM plans, compare Taiwan, China eSIM and Hong Kong, China travel eSIM. If your trip covers several countries, a Asia plan saves buying twice.
This is why automatic carrier switching matters on a Japanese trip. A profile that can move between Docomo, au, SoftBank and Rakuten covers the regional gaps that any single-carrier plan cannot.
Do I need to enter APN settings in Japan?
The APN screen matters most on plans bought inside Japan, where the profile does not always carry its own values. Here are the values per carrier, the narrow set of cases needing manual entry, and the exact menus.
APN values for Docomo, au and SoftBank eSIMs
You will only need these if you bought a SIM or eSIM directly from a Japanese carrier or a budget brand on its network. A travel eSIM in Japan carries its own APN values and needs no manual entry.
| Carrier | APN | Username | Password |
|---|---|---|---|
| NTT Docomo | spmode.ne.jp |
blank | blank |
| au (KDDI) | au.au-net.ne.jp |
blank | blank |
| SoftBank | smile.world |
blank | blank |
| Rakuten Mobile | rmobile.jp |
rm |
0000 |
Leave username and password empty except on Rakuten Mobile, where the carrier specifies rm and 0000. Should an operator insist on a value, the paperwork shipped with the profile will name it.
APN configuration in Japan
Most Japanese profiles configure themselves; these are the narrow cases that do not.
- An aging handset that doesn’t collect carrier settings automatically
- A profile installed with a manual activation code instead of a QR scan
- A carrier-issued prepaid eSIM where automatic configuration did not run
- Almost never on a travel eSIM, which is the point of a managed profile
Japan: when the APN won’t auto-load
- iPhone: open Settings → Cellular → tap the eSIM line → Cellular Data Network → key in the APN
- Android: Settings → Connections → Mobile Networks → Access Point Names → add a new APN
After saving, restart the phone. When data still refuses to work, confirm the Japanese profile owns the data line before touching other settings.
Japan eSIM activation and troubleshooting
A single sweep of this section covers everything from clean install to working data, including the failure patterns a Japanese network can produce, in the order they typically appear.
Japan eSIM: installation walkthrough
| # | Check | What good looks like |
|---|---|---|
| 1 | Phone is not carrier locked | No SIM restrictions listed in About → Carrier Lock |
| 2 | Phone supports eSIM | *#06# shows an EID, or the compatibility checker confirms your model |
| 3 | QR code and activation code saved | Screenshot on the phone and in cloud storage |
| 4 | Profile installed before departure | Install on Wi-Fi at home; it connects when you land |
| 5 | Data line and roaming set | eSIM selected for mobile data, data roaming on |
Do step 4 at home. Narita, Haneda and Kansai arrival halls have congested Wi-Fi exactly when you need it most, and a profile you install on the ground competes with everyone else’s.
Which Japan carrier should you pick: Docomo vs au?
The ordinary route — Add eSIM, QR scan, data-line choice — is in our activation walkthrough. What differs across Japanese networks:
- Docomo via IIJ: activated from the FamilyMart slip and the dedicated website; manual APN entry is required
- au via povo: activated at Lawson from the QR and PIN on the SIM card; eSIM on au’s network
- SoftBank via LINEMO: resident route, app-based with residence-card eKYC; not a tourist flow
- Rakuten Mobile: resident route, app-based after eKYC; not a tourist flow
- Travel eSIMs: install by QR code, and the same profile roams onto whichever of Docomo, au, SoftBank or Rakuten is strongest
Four remedies for a stalling Japan eSIM
General activation errors — a profile that will not download, a scan that fails, an eSIM that installs but never registers — are covered in our eSIM troubleshooting resource. Japan has its own set of four patterns, listed below.
A. The eSIM will not install
- Carrier Lock showing No SIM restrictions means the phone is unlocked
- Check the QR code is clean and unscanned, most are single-use
- Ask whether the profile is queued on the carrier side
B. Installed, but no signal bars
- Re-check the lock status
- Settings → Cellular → Network Selection → pick Docomo, au, SoftBank or Rakuten manually instead of automatic
- Do a network reset followed by a full restart
C. Signal bars, but no internet
- Re-read the APN row for your carrier in the table
- Make sure the Japan eSIM is the line carrying data rather than your home SIM.
- Check you have not hit a fair-usage throttle; unlimited travel plans often drop to a floor after a daily cap
D. Dead zones on the train or in the mountains
- If you are on Docomo, confirm your phone supports Band 19; without it you fall back to Bands 1 and 3
- Switch to SoftBank or au, which use globally aligned low bands, or use a multi-network eSIM
- Download offline maps before the Shinkansen or a trailhead
What to collect before you contact Japanese support
| Information | Where to find it |
|---|---|
| Order or account number | Confirmation email |
| Phone model and OS version | Settings → About |
| EID | *#06# |
| Screenshot of the error | Take it before the screen changes |
| Current APN settings | Settings → Cellular Data Network |
| Data roaming status | Settings → Cellular → your eSIM line |
| Steps already tried | Keep a short list |
Japan eSIM FAQ
Can I buy a tourist eSIM directly from NTT Docomo?
Not as a walk-up visitor. Docomo’s own eSIM rides on resident plans like ahamo and needs a Japanese address and residence card. Visitors reach Docomo’s network through IIJmio Japan Travel SIM at FamilyMart, or through a travel eSIM, both of which use Docomo capacity without a contract.
Does au sell a prepaid eSIM that visitors can buy?
Yes, and it is the only national carrier that does. au’s povo brand sells a tourist eSIM at Lawson from 1 July 2025, with plans from ¥2,200 for 3 GB over 7 days to ¥4,500 for unlimited over 7 days, paid in cash with no residence card. It connects to au’s network in about three minutes.
Can international visitors get a SoftBank eSIM?
Not directly. SoftBank’s LINEMO brand needs a residence card and a Japanese payment method, and its eSIM tiers are limited to permanent or special permanent residents. Visitors get SoftBank data through a travel eSIM that leases its network, which is where SoftBank’s best-in-class video and gaming scores are still useful.
Is Rakuten Mobile a good eSIM choice for a short visit?
Rakuten is the fastest and most consistent network in Ookla’s 2H 2024 data, but its own eSIM needs a residence card, a Japanese address and a Japanese card, so a short-stay tourist cannot sign up. Rakuten reaches visitors through travel eSIM brands that ride its network instead.
Docomo vs au: coverage compared
NTT Docomo, on the evidence. It led Ookla’s 5G availability at 43% and wins on breadth of coverage, especially in Hokkaido, Tohoku and the mountains, because its low-band layer uses Band 19. The catch is that many foreign phones lack Band 19, so they see Docomo’s coverage only on Bands 1 and 3. A multi-network eSIM avoids that trap.
Best-coverage network in Japan
Docomo routes its foundational coverage through Band 19 at 800 MHz and its 5G through n79 at 4.5 GHz, neither of which ships in most North American or European phones. Without those bands your device clings to Bands 1 and 3, which are urban layers, so tunnels, rural roads and ski resorts drop out. SoftBank is the most foreign-phone-friendly network because it uses the global Band 8 and n77.
The Japan SIM registration process
From 1 April 2026, yes, for almost everyone. The Ministry of Internal Affairs and Communications requires all data SIM and eSIM buyers, tourists and residents alike, to show identification: a passport for tourists, a residence card for residents. The rule applies in stores and online, so travel eSIM checkouts now ask you to upload a passport photo before the profile downloads.
Should I buy from a Japanese carrier or use a travel eSIM?
Direct means one network, carrier-issued provisioning, and often a residence card or Japanese payment method; in exchange you get a real local number and monthly billing. A travel eSIM means instant delivery, no paperwork, automatic switching across Docomo, au, SoftBank and Rakuten, and a fixed upfront price. Short trip: travel eSIM. Living in Japan: direct.
Dealing with a locked phone in Japan
Ask the carrier it is locked to. Under MIC guidelines effective September 2019, carriers must offer SIM-unlock removal free through their online or phone channel, and phones sold since May 2015 are unlockable once any mandatory lock-in period, around 100 to 180 days, has passed. Unlock requests on paid-off handsets usually clear in hours. iPhone owners can read the lock state in Settings → General → About → Carrier Lock.
Checking IMEI and EID for Japan
It needs to be unlocked and eSIM-capable, and it helps if it supports the bands each carrier uses. Check both in one pass with the eSIM compatibility tool, which covers EID support and the Band 19 question for Docomo. If the install step is the unclear part, how eSIM installation works explains it.
What if my Japan eSIM stops working on the Shinkansen?
Work the Japan-specific patterns above in order, lock status, network selection, APN and data line, then profile reinstall, and if it still fails the wider error catalogue in the eSIM activation fixes guide covers the rest. On the bullet train, prefer Docomo for tunnel consistency and always download offline maps before you board.
The chip that stores a Docomo or au profile
The chip is already soldered into your phone — what a Japanese purchase adds is a profile. The carrier pushes it down, the chip keeps it, and the line then behaves normally. For more, the eSIM activation explainer covers the delivery, activation codes included.
More questions? Browse the full FAQ
The Japan eSIM carriers: Docomo, au and SoftBank
- The carrier-level figures on this page rest on the Ookla Speedtest Connectivity Report for Japan, July to December 2024 — the per-carrier report supplies Rakuten Mobile’s 89.9% consistency and 151.16 Mbps median 5G download, SoftBank’s 75.91 video and 80.94 gaming scores, Docomo’s 43% 5G availability and au’s 115.24 Mbps median 5G download.
- Japan’s national median mobile download and world rank come from the Ookla Speedtest Global Index — the Japan entry, updated monthly.
- The SIM-unlock rules and the April 2026 identity-verification requirement are documented by the Ministry of Internal Affairs and Communications (MIC) — the national regulator.
- au’s tourist eSIM prices, Lawson availability and activation steps were reported in the KDDI News Room — the povo2.0 Japan SIM announcement.
- The per-gigabyte figure for Japan is drawn from Cable.co.uk worldwide data pricing — the full country table.
These are third-party readings only. Your own results will shift with the phone you carry, the band it camps on, and how loaded the nearby mast is.
Get your Japan eSIM ready before you fly
Roami’s Japan eSIM moves between Docomo, au, SoftBank and Rakuten Mobile so you stay online from Tokyo to Hokkaido. Claim the free Japan trial eSIM to test coverage, or take 20% off Japan eSIM plans with code WEB20.
First-time buyers, single use
