Japan eSIM Not Working? 7 Fixes That Solve 95% of Cases
TL;DR: 95% of “no data” cases are fixed by: ① turn ON Data Roaming for the eSIM line, ② set the eSIM as your data line, ③ restart the phone. Work through the list below in order.
Before anything: 2 facts to know
- Travel eSIMs connect as roaming — “Roaming” showing on your screen is normal and costs nothing extra.
- Most plans activate on arrival in Japan (or on your chosen start date). Installing at home and seeing “No Service” before departure is expected.
The 7 fixes, in order
1. Turn on Data Roaming (fixes most cases)
- iPhone: Settings › Cellular › [your eSIM] › Data Roaming ON
- Android: Settings › Network & internet › SIMs › [your eSIM] › Roaming ON
2. Set the eSIM as the data line
- iPhone: Settings › Cellular › Cellular Data › select the travel eSIM
- Android: Settings › SIMs › Mobile data › select the travel eSIM
Keep your home SIM active for calls/SMS, but make sure it is not the data line (that would mean expensive home-carrier roaming).
3. Restart the phone
Not a joke — after any SIM change, a restart forces the modem to re-register. Do it before deeper fixes.
4. Toggle Airplane Mode
10 seconds ON → OFF. Forces a fresh network search without a full restart.
5. Select the network manually
If auto-connect picks a partner network the plan doesn’t support:
- iPhone: Settings › Cellular › [eSIM] › Network Selection › turn OFF Automatic → choose the network named in your plan email (e.g. SoftBank)
- Android: Settings › SIMs › [eSIM] › Automatically select network OFF → choose it manually
6. Check / set the APN
Most plans configure APN automatically. If your plan email lists an APN and you still have no data:
- iPhone: Settings › Cellular › [eSIM] › Cellular Data Network › enter the APN exactly
- Android: Settings › SIMs › [eSIM] › Access Point Names › add it, save, select it
7. Confirm the plan has started (and has data left)
Check your plan’s start date and data balance from the link in your confirmation email. A plan set to start tomorrow will not connect today; an exhausted plan may drop to a slow speed or stop.
Still stuck?
Contact support with: your phone model, what step failed, and a screenshot of Settings › Cellular. We answer fast, and every plan is covered by our money-back guarantee — if we can’t get you connected, you get a refund. That’s the whole point.
Prevent it next time
Install over Wi-Fi before you fly, and skim our setup guide — 3 minutes of prep beats airport debugging.