Ubigi Japan eSIM Not Working? Fix No Service, APN & Data Issues
If your Ubigi Japan eSIM isn’t working, don’t spiral, it’s usually one of a few boring settings issues (roaming toggle, wrong data line, APN, or the eSIM not actually installed/active). Here’s the fastest way to get signal back.
6/7/20263 min read
If your Ubigi Japan eSIM isn’t working, don’t spiral, it’s usually one of a few boring settings issues (roaming toggle, wrong data line, APN, or the eSIM not actually installed/active). Here’s the fastest way to get signal back.
Do this first (2-minute fix checklist)
Restart your phone (yes, really).
Turn Aeroplane Mode ON for 10 seconds, then OFF.
Make sure you’re using the Ubigi eSIM for Mobile Data (not your home SIM).
Turn Data Roaming ON for the Ubigi eSIM (Ubigi needs this in Japan).
If you have two SIMs active, temporarily turn OFF your home SIM to test.
If it still says “No Service”, manually select a network (steps below).
If you haven’t set it up yet (or you’re not sure you did), use my full guide here:
And if you want the simple “what to buy + what plan” version, start here:
Symptom 1: Ubigi eSIM shows “No Service” / “SOS” / no bars in Japan
This is the most common panic moment. Try these in order:
1) Check you’re on the right line (dual SIM mistake)
Go to your SIM settings and confirm Ubigi is selected for Mobile Data.
If your phone keeps clinging to your home SIM, switch the home SIM off for 2 minutes to force the eSIM to connect.
2) Turn Data Roaming ON (Ubigi usually needs it)
Even if you hate roaming, this is the toggle that often fixes it.
iPhone: Settings → Mobile Data → (Ubigi line) → Data Roaming ON
Android: Settings → Network & Internet → SIMs → (Ubigi) → Roaming ON
3) Manually choose a network (auto can fail)
Sometimes the phone just doesn’t pick a partner network properly.
Go to the Ubigi eSIM network settings
Turn Automatic network selection OFF
Wait for networks to load
Try one, wait 60–90 seconds, then try the next if needed
4) Update your phone (annoying, but it matters)
Carrier settings and eSIM behaviour can be buggy on older versions.
Update iOS/Android
Then restart again
Symptom 2: Ubigi eSIM is installed but “stuck activating”
If it’s stuck on “Activating…” for ages:
1) You might not have a stable connection during activation
Activation often needs Wi‑Fi or stable data.
Connect to Wi‑Fi
Restart the phone
Leave it on charge for 5–10 minutes (sounds silly, helps sometimes)
2) Remove and reinstall (only if you have the QR/details)
If you still have your installation details and you’re confident:
Delete the Ubigi eSIM
Reinstall it using the original QR / activation method
If you don’t have the details anymore, don’t randomly delete things, you can lock yourself out and waste time.
Symptom 3: You have signal but no internet / apps won’t load
This is usually a data line / APN issue.
1) Make sure Ubigi is the data line
Confirm Mobile Data = Ubigi
Turn Mobile Data Switching OFF (iPhone) so it doesn’t bounce between SIMs
2) Check APN (Android especially)
On many Android phones, APN is the difference between “bars” and “actual internet”
Go to Access Point Names (APN) under the Ubigi SIM
If there’s an Ubigi APN option, select it
If it’s blank or clearly wrong, reset network settings (below) and try again
(APN menus vary wildly by Android brand, if you tell me your phone model, I’ll give the exact path.)
3) Reset network settings (the nuclear option that works)
If you’ve tried everything and it’s still dead:
iPhone: Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings
Android: Settings → System → Reset options → Reset Wi‑Fi, mobile & Bluetooth
This will wipe saved Wi‑Fi passwords, but it often fixes eSIM data issues instantly.
Symptom 4: Ubigi works, but hotspot/tethering won’t work
Hotspot problems are common with travel eSIMs because phones get weird with dual SIM + roaming.
Try:
Make sure Ubigi is the Mobile Data line
Turn Data Roaming ON
Restart
Toggle hotspot OFF/ON
If you’re on iPhone, set Maximise Compatibility ON (if available)
If you need hotspot reliably, I’d treat it as its own setup step (and test it before you leave your accommodation).
The “I’m in Japan and I need this working right now” checklist
If you’re standing in a station with no signal and your patience is gone:
Restart phone
Aeroplane Mode ON/OFF
Ubigi = Mobile Data
Data Roaming ON
Home SIM OFF (temporarily)
Manual network selection
Reset network settings (last resort)
Then go back to the main Japan eSIM page for plan/setup context.
Ubigi Japan eSIM Not Working: FAQ
Why does my Ubigi eSIM say “No Service” in Japan?
Usually because data roaming is off, the phone is using the wrong data line, or it failed to auto-select a partner network. Manual network selection fixes a lot of cases.
Do I need to turn roaming on for Ubigi?
In many cases, yes. It feels wrong, but it’s often required for the eSIM to connect properly.
Should I delete and reinstall the Ubigi eSIM?
Only if you still have the QR/installation details and you’ve tried the basic fixes first. Otherwise you can make it worse.
What if nothing works?
At that point, you’ve likely got an activation/account issue or a network-side problem. Use Wi‑Fi to access Ubigi support, and keep your screenshots of the error/status screens.
Quick link if you’re starting from scratch
If you want the clean “buy this, do this, don’t mess it up” version:
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