Four minutes at home · nothing at the airport
Setting up your Japan eSIM
Do this on your own wifi the night before. Every eSIM problem that ruins a first day is a problem that was solvable at home with a working connection.
*#06#. If an EID appears, your phone takes an eSIM. Buy the plan at home, install the profile on your own wifi, label the line "Japan", and leave it switched off until you land. On arrival: Japan line on for data, home line on for calls with data roaming off. If nothing attaches after five minutes, set network selection to manual and pick the carrier your plan rides. Checked September 4, 2026.Three things to check before you buy anything two minutes
- Does the phone take an eSIM? Dial
*#06#. An EID in the list means yes. No EID means no eSIM, and the alternatives are a physical SIM or a rented router. Most iPhones from the XS onward and most flagship Android handsets from about 2020 qualify. - Is the phone carrier-locked? A locked handset will install the profile and then refuse to use it. Ask your carrier to unlock before you travel; in the US this is usually free once the device is paid off, and it can take a day or two.
- Which network does the plan ride? This is the Japan-specific one. GigSky is on NTT Docomo and SoftBank, Airalo on KDDI and SoftBank, Yesim on KDDI and Docomo, and Saily does not say. If your route leaves the cities, this decides which plan to buy.
Installing the profile at home, on wifi
iPhone
- Buy the plan and open the confirmation on the phone, or scan its QR code from another screen.
- Settings, Cellular, Add eSIM. Most providers now offer one-tap install from their app, which is easier than the QR route.
- When asked, label the line Japan. Not "Secondary". You will be toggling this in a queue.
- Turn the new line off for now. Nothing starts counting until it connects in Japan, but leaving it on invites the phone to try.
- Check Settings, Cellular, Cellular Data still shows your home line. You are not switching anything until you land.
Android
- Buy the plan and open the confirmation, or have the QR code ready on another screen.
- Settings, Network and internet, SIMs, Add eSIM or the plus button. Samsung puts it under Connections, SIM manager.
- Name it Japan when prompted.
- Leave it disabled until you arrive.
- Confirm your home SIM is still the default for data, calls and SMS.
What to do when the plane lands thirty seconds
- Turn airplane mode off and wait. Give it two or three minutes before touching anything; the phone is scanning for networks it has never seen.
- Enable the Japan line. iPhone: Settings, Cellular, tap the Japan line, turn it on, then set Cellular Data to it. Android: Settings, SIMs, enable, then set as mobile data.
- Leave your home line enabled for calls and SMS, with data roaming OFF. This is the toggle that stops the $12-a-day charge while keeping your own number live for bank verification codes.
- Check what you attached to. The carrier name in the status bar tells you whether you are on DOCOMO, KDDI or SoftBank. On a plan that lists two networks, this is worth a glance.
It is not working: symptom to fix in the order to try them
| Symptom | Most likely cause | Fix |
|---|---|---|
| No service at all, five minutes after landing | The phone has not finished scanning, or the line is not enabled | Toggle airplane mode on and off. Then check the Japan line is enabled and set as the data line. |
| Connected, but no internet | Cellular data is still pointed at your home line | iPhone: Settings, Cellular, Cellular Data, select the Japan line. Android: SIMs, mobile data, select it. |
| Still nothing after ten minutes | The phone has latched onto a network your plan cannot use | Turn off automatic network selection and pick your plan's carrier by hand. NTT DOCOMO, sometimes listed as ドコモ, for GigSky; KDDI or au for Airalo; SoftBank may appear as ソフトバンク. |
| Works in the city, dies in the mountains, or the phone reads 圏外 | This is coverage, not a fault. 圏外 (kengai) is what a Japanese handset shows instead of "No Service" | Nothing to fix. If it happens repeatedly, your plan is on the wrong carrier for your route. See the network page. |
| Very slow, but connected | You have crossed a daily cap on an unlimited plan | Wait for midnight Japan time, when the allowance resets. The caps are here. |
| Data runs out early | Photo backup or app updates over cellular | Turn off cellular backup in Photos and app updates over mobile data. More ways to use less. |
| Some websites or services behave oddly | Your traffic is exiting the country somewhere unexpected | Known on some Saily plans in Japan, where reviewers report a Hong Kong exit. Not fixable at your end; a different provider is the answer. |
| Profile will not install | Carrier lock, or no wifi | Install on wifi only. If it fails on wifi at home, the handset is probably locked and the provider's support is the next step. |
The night-before checklist seven lines
- Dialled
*#06#and saw an EID. - Phone unlocked, confirmed with the carrier rather than assumed.
- Plan bought and profile installed, on home wifi, labelled Japan.
- Offline maps downloaded for every city on the route, and the Japanese language pack downloaded in Google Translate.
- Cellular photo backup switched off.
- LINE installed and verified on your home number, while you still have signal on it.
- GigSky's free 100MB installed as a spare, because it costs nothing and expires on its own.
Setup questions short answers
When should I install my Japan eSIM?
At home, on your own wifi, the day before you fly. The plan does not start counting until the profile connects to a Japanese network, so there is no cost to installing early and a real cost to trying it at the airport, where you have no working connection to download the profile with.
Does my phone support eSIM?
Dial *#06#. If an EID appears in the list alongside the IMEI, yes. Most iPhones from the XS onward and most flagship Android handsets from around 2020 support it. Japanese-market phones, older handsets and some managed work devices often do not.
Can I keep my regular number while using a Japan eSIM?
Yes, and this is the main reason to prefer an eSIM over a physical Japanese SIM. Leave your home line enabled for calls and texts with data roaming switched off, and set the Japan eSIM as your data line. You keep receiving verification codes on your own number without paying a roaming day pass.
Why is my eSIM not connecting in Japan?
In order: the line is not enabled, cellular data is still pointed at the home line, or the phone has attached to a network your plan is not permitted to use. The third one is fixed by turning off automatic network selection and choosing your plan's carrier by hand, NTT DOCOMO for GigSky or KDDI for Airalo.
Do I need to remove my physical SIM?
No. An eSIM is a second line, not a replacement. Keep the physical SIM in the tray with data roaming off. Removing it means losing calls and texts on your own number, which is exactly what you are trying to avoid.
Install the free one tonight
GigSky gives away 100MB for seven days with no card. Install it now, land with a working phone whatever else happens, and use it to see which Japanese network your handset actually attaches to before you commit to a paid plan.
Get GigSky free 100MBSources & freshness: Menu paths verified against current iOS and Android releases and vary slightly by manufacturer, particularly on Samsung. Network permissions from each provider's published Japan coverage record on September 4, 2026. The Saily exit-address reports come from traveler reviews on esimdb and are traveler reports rather than a tested finding. How we test.