What breaks when you travel on a data-only eSIM — checked country by country.
JAPAN / AFTER HOURS · AI-generated editorial image
Japan · checked 11 Sep 2026
Japan app access depends on more than mobile data. Some services need a Japanese number or a voice line. Choose your activities, then review the app-specific requirements and source updates.
Japan · checked 11 Sep 2026
Tick what you actually plan to do. Nothing is sent anywhere; this runs in your browser.
Saved only in this browser. A shared link contains your activity choices and home-SIM setting. It opens with the latest available findings.
Every claim here is tagged with where it came from and how sure we are. When a company says it in its own help pages, we say so. When it is traveller reports, we say that too, and we do not dress it up.
Almost every “do I need a local SIM?” argument online is two separate questions wearing one coat.
Gate A — Possession check
Any SMS-capable number passes, including your home one. A data-only eSIM has no number at all, so it fails this on its own — but it passes if you keep your home SIM active alongside it.
Gate B — Japanese number required
No foreign number passes, no matter which carrier issued it — so neither a data-only eSIM nor your home number gets you in.
Ordered by how hard they block, not by how well known they are.
Rechecked against official help; other findings retain their earlier date.
Japan's most-used QR payment app
PayPay's own help page states that overseas mobile numbers cannot be used and that you need a Japanese mobile number to register.
Rechecked · 2026-10-29 · Open official source ↗
海外の携帯電話番号は利用できません。日本の携帯電話番号をご用意ください
NTT Docomo's payment app
Registration accepts only an 11-digit number issued in Japan. Overseas numbers are outside the scope of the service.
Rechecked · 2026-10-29 · Open official source ↗
Large concert and event ticketing site
Sign-up appears to verify a Japanese mobile number (070/080/090) by placing a call. We could not find a company policy document stating this, so treat it as reported rather than confirmed.
Further verification needed · Open official source ↗
Major food delivery platform
This one blocks by line type. Demae-can's help page says landlines and mobile numbers without a voice contract cannot be registered — so a data-only line is excluded at the source, Japanese or not. The page does not say whether a foreign number with voice calls is accepted.
Rechecked · 2026-10-29 · Open official source ↗
固定電話番号や音声契約のない携帯電話番号はご登録いただけません
Japan's largest taxi-hailing app
GO added sign-up with overseas mobile numbers in November 2023. It also publishes a fallback for people who cannot receive an SMS at all: identity check by passport photo and a selfie, inside the same app. That fallback is what makes it usable on a data-only eSIM with no other line.
Rechecked · 2026-10-29 · Open official source ↗
The default messaging app in Japan — restaurants, hotels and shops use it
LINE sign-up depends on your country of residence. Phone verification is used in Hong Kong, Japan, Korea, Taiwan and Thailand; other countries use Apple or Google. Check the official route for your residence.
Requirements vary — review the source · Open official source ↗
New account creation
Uber verifies by SMS to any number and does not appear to require a Japanese one. We are working from Uber's global help material rather than a Japan-specific policy page, so this is reported rather than confirmed for Japan.
Further verification needed · Open official source ↗
Depends entirely on whether you already have an account
Creating a new account needs the SMS step, same as Uber rides. An account you opened at home is the useful case: travellers report it keeps working in Japan on data alone, because ordering and courier chat both run inside the app.
Further verification needed · Open official source ↗
Trains, buses, convenience stores, vending machines
Bought with cash at a station. There is no account, no app and no phone number involved at any point.
Further verification needed · Open official source ↗
JR East's official card for overseas visitors
Issued to visitors without a membership account — no sign-up, so no phone number to verify.
Further verification needed · Open official source ↗
Japan's identity-check law for mobile contracts currently covers voice services. A bill submitted to the Diet on 24 March 2026 extends it to data communication services as well, and adds a clause for verifying foreign nationals with no address in Japan — by passport number, in place of an address.
Some travel sites state that eSIMs bought abroad are carved out of this. That carve-out does not appear anywhere in the bill text. What the bill does do is attach the duty to a Japanese carrier concluding a service contract, and to agents acting on that carrier's behalf.
So the question that actually decides it is whether your eSIM is a Japanese contract or a foreign one roaming onto a Japanese network. Ubigi and aloSIM both describe their service as roaming partnerships with local operators, which points away from a Japanese contract — but that is our reading of the structure, not legal advice, and the bill's commencement date has not been confirmed.
We list a provider only when we have checked, from the company's own material, how it actually connects in the destination country. Right now that is two.
Paid link disclosure
Roamclarity earns a commission when someone buys a Ubigi plan through the link below. We earn nothing from aloSIM — we have no affiliate relationship with them and the link is a plain one. The checks, the verdict and the order of everything on this page were settled before any commercial arrangement existed, and none of it is ranked by what pays us.
Paid link — we earn a commission
Ubigi's own help centre describes its coverage as roaming partnerships with local operators in over 200 destinations. Source
Go to UbigiNo affiliate relationship — plain link
aloSIM's support material states it does not run its own network and that the connection is treated as roaming by your phone — its setup guide tells you to switch data roaming on when you land. Source
Go to aloSIMNone of them give you a phone number. That is the whole point of the product, and it is also the thing that trips people up: every sign-up above that asks for an SMS is asking for something a data-only eSIM structurally cannot provide. The usual fix is not a different eSIM — it is keeping your home SIM switched on for SMS while the eSIM carries the data.
Korea works differently, and we cover it in depth on a separate site.
Korea: do you need a Korean number? →