Install before you fly, land connected, skip the airport SIM counter. This page lists travel eSIM providers that state which Japanese network their plans run on, and sets out what each one says about tethering, speed limits and phone numbers.
What to compare
Check this
Why it matters
Network used
Japan has four nationwide mobile networks — SoftBank, docomo, au (KDDI) and Rakuten Mobile. Official 5G population coverage (MIC, March 2025): SoftBank 97.1%, au 94.6%, docomo 89.4%, Rakuten Mobile 61.1%. Population coverage counts where people live, so cities and suburbs are well served on the big three — differences show up mostly in deep rural areas. The providers on this page do not run networks of their own — each resells access to a Japanese network, and each states on its own site which one. That statement is what we check.
Data-only vs voice
Most travel eSIMs are data-only. You keep your home number for SMS codes — check roaming cost for that.
Tethering
Not all plans allow hotspot use. Essential if you carry a laptop.
Top-up method
In-app top-up beats buying a new plan mid-trip.
Activation policy
Some plans start counting days at purchase, others at first connection. This decides whether you lose days before you land, so check the provider's own page before buying — we have not verified this per provider, and we will not state it until we have.
Coverage figures: Ministry of Internal Affairs and Communications (MIC), 5G deployment status, FY2024 year-end — carrier-by-carrier 5G population coverage as of 31 March 2025.
If you need a Japanese phone number
Most travel eSIMs are data-only. That is enough for maps, translation and messaging apps — but it does not give you a Japanese number, and some services in Japan will only send a verification code to one.
What you get
Japanese number
Can receive SMS codes
Available before you fly
Data-only eSIM (Airalo, Mobal data plans, Sakura Mobile)
No
No
Yes — delivered instantly
Japanese mobile number (Mobal voice eSIM)
Yes
Yes
Yes, but an ID check, a proof-of-address upload and postal delivery of up to 30 business days mean you must order well ahead.
Mobal checks your ID before it will issue the voice eSIM, so it cannot email you the access code. It posts a physical eSIM Access Code instead — free worldwide — and it also requires you to upload proof of your shipping address. Its own shipping table quotes international mail from 2–5 business days (Hong Kong, Taiwan, the UK) to 15–30 business days (Australia, Canada, Israel), so the wait depends on where you are. You can also collect the code at one of its pick-up points in Japan by showing your ID. Order well ahead if you need the number on arrival.
Why this matters on arrival: the taxi apps ask for an SMS code when you sign up, and S.RIDE states it cannot be used with numbers from some overseas carriers — see our ride-hailing guide.
How we choose which providers to list
We list a provider only if it states, on its own website, which Japanese mobile network operator its Japan service runs on. If a provider does not publish that, we have no primary source for it — and we do not guess, so we cannot list it here.
We apply that test to the specific plan we describe. Where a provider's own summary or FAQ disagrees with its plan pages, we follow the plan pages and do not quote the summary.
That is the only test. We take no payment, commission or free service from any provider, and we use no affiliate links anywhere on this site.
Providers are listed alphabetically. We do not rank them.
Provider candidates
The right plan depends on your trip length, data needs and how each plan counts its days, so we set out the facts and leave the choice to you. The criteria above are the whole test.
"Unlimited" does not always mean unlimited full-speed data. What happens when you reach a provider's limit differs — some slow you down, some stop the connection, and some say nothing at all about it. Below is what each provider states about its own plans, and where it states nothing, we say so.
Airalo
Its Japan eSIM page states the plan operates on the Softbank and KDDI networks. Marketplace model with Japan-specific and regional Asia plans; app-based top-ups.
Tethering: Supported if your device and the network allow it. Stated in Airalo's help centre, not on the Japan plan page.
Speed limit: Differs by package type. Its 6 unlimited packages carry a fair usage policy: "Lower speed rate of 1 Mbps after 3 GB usage per day." Its 11 fixed-data packages state no such policy — instead Airalo's plan details say the data connection stops once the package data runs out.
Plan pages name the network per plan. The data-only Japan Tourist eSIMs run on Docomo. The 5G unlimited data eSIM, sold in lengths from 3 to 31 days, runs on KDDI. Mobal's separate voice eSIM comes with a Japanese 070/080/090 number and runs on Docomo — see the note below on ID checks and delivery.
Tethering: Depends on the plan. Mobal states some of its services support tethering and that it cannot guarantee the feature works with all devices. The unlimited plan states a hotspot allowance that grows with plan length, from 2 GB at 3 days to 30 GB at 31 days.
Speed limit: Differs by plan. Each of the 9 fixed-data Tourist eSIMs states that once its high-speed data is used up, the eSIM keeps you connected at up to 200 kbps for the rest of the plan — the connection is slowed, not cut. The unlimited plan's own page states no speed limit; it says the plan "really is unlimited".
Each travel eSIM plan names its network: the 3 GB/day plans run on docomo and the unlimited plans run on au. All of them are data-only, with no Japanese phone number.
Tethering: Available on all travel eSIM plans. The 3 GB/day plans state no cap; the unlimited plans state a hotspot allowance that grows with plan length, from 2 GB to 30 GB.
Speed limit: Applies to the 3 GB/day plans only. Sakura Mobile states these carry a fair usage policy: you will not be disconnected, but the speed is limited to 200 kbps after 3 GB of data in a day. Its unlimited plans state no such limit — the page calls them "truly unlimited" with no daily limits.
Its product page states the plan runs on all four Japanese networks — NTT docomo, KDDI/au, SoftBank and Rakuten Mobile. That statement is what we checked, not how the networks perform. Simbye runs no network of its own: it says it partners with 700+ tier-1 carriers worldwide. The Japan plans are data-only, with no Japanese phone number. Its plan-selector values were checked in a rendered browser on 2026-07-29, because they do not appear in the page source.
Tethering: Supported. The product page lists Hotspot as Yes in its technical specs, and its FAQ says tethering works.
Speed limit: Applies to the unlimited plans only. Simbye states a fair use policy of 2 GB at high speed per day, then unlimited at 1 Mbps. Its fixed-data plans state no speed policy, and say nothing about what happens once the data runs out.
Even before your eSIM is running, both airports have free Wi-Fi you can use to activate or buy a plan, send the messages people are waiting on, and skip the SIM-counter queue entirely.
Free Wi-Fi on arrival
Haneda — connect to HANEDA-FREE-WIFI in all three terminals. It does not reach inside shops (airport lounges aside), and the airport notes some areas can be harder to connect in. Haneda free Wi-Fi (official) →
Narita — connect to FreeWiFi-NARITA across every terminal and on the inter-terminal connecting bus. It has no pre-set security, so the airport recommends using a VPN, and speeds drop when the network is busy. Narita Wi-Fi & power (official) →
If the mobile signal is weak deep inside a terminal, this free Wi-Fi is your fallback for finishing eSIM setup or messaging.
Charging and power
Haneda — free charging corners in every terminal. In Terminal 3 there are two on the 1st floor, six on the 2nd and two on the 3rd, plus more airside; bring your own adapter if you charge over USB Type-C. Haneda charging corners (official) →
Free Wi-Fi exists at the airports and many stations, but it is patchy in between — and you want maps and train search exactly when you are moving. A data eSIM removes the gamble for a few dollars a day.
Can I buy a SIM at the airport instead?
Yes — both airports have SIM counters and vending machines. They work fine; you simply pay airport prices and spend arrival time on it. Installing an eSIM before you fly does the same job without the queue.
Will my phone work with an eSIM?
Most phones from the last several years support eSIM, but carrier-locked phones may not accept one. Check that your phone is unlocked before buying any plan.
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