eSIM not working in Japan
Your Drift Asia eSIM has no data in Japan? Here is the real fix, step by step, iPhone and Android, with Japan operator APN reference.
Networks in Japan
Japan has 4 major operators, all compatible with travel eSIMs:
| Operator | Coverage | Technology |
|---|---|---|
| NTT Docomo | 1er réseau, meilleure couverture rurale et montagne | 4G/5G |
| au (KDDI) | 2e réseau, bonne couverture urbaine et Shinkansen | 4G/5G |
| SoftBank | 3e réseau, forte présence Tokyo/Osaka | 4G/5G |
| Rakuten Mobile | 4e opérateur, couverture en expansion, roaming KDDI hors zones propres | 4G/5G |
Your eSIM connects to one of these networks (most often NTT Docomo). 4G coverage spans the large majority of tourist and urban areas.
Diagnosis in 5 steps (in this order)
Work through these before anything else. Nine times out of ten, the fix is in this list.
Steps 2 and 3 fix the large majority of cases. Data roaming is required for any travel eSIM. It does not add charges on a Drift Asia plan.
Airplane mode as a diagnostic tool
Toggling airplane mode forces the phone to detach from the network and search fresh. It is faster than a full restart and clears most handover issues (when the phone stays attached to a ghost signal after a long flight). If after the toggle you see the operator name on screen but still have no data, the issue is almost certainly roaming (step 2) or data line (step 3).
Signal bars vs. data
A common trap: you see signal bars but nothing loads. Bars mean the phone detects the network, not that it is authorized to exchange data. That is exactly what happens with roaming off: signal is there, but the network refuses your data packets. Turn roaming on and data resumes.
APN in Japan: do you need to set it?
No, in 99% of cases. Your travel eSIM sets its own APN automatically via the installed profile.
Do not enter your home operator's APN or a NTT Docomo APN found online into the eSIM line. Those are APNs for local physical SIMs, not travel eSIMs. Entering one overwrites the profile's APN and breaks your data instead of fixing it.
For reference only (do NOT enter these on your eSIM line):
| Operator | Primary APN | Alt APN | Note |
|---|---|---|---|
| NTT Docomo | spmode.ne.jp | mopera.net | 1er réseau, meilleure couverture rurale et montagne |
| au (KDDI) | uno.au-net.ne.jp | -- | 2e réseau, bonne couverture urbaine et Shinkansen |
| SoftBank | plus.4g | jpspir | 3e réseau, forte présence Tokyo/Osaka |
| Rakuten Mobile | rakuten.jp | -- | 4e opérateur, couverture en expansion, roaming KDDI hors zones propres |
Manual APN entry only if support asks with a specific value. Full procedure: Do I need to set an APN?
Country-specific notes for Japan
Tokyo and Osaka metro
The Japanese metro has 4G coverage on nearly all lines, including tunnels. Some deep stations on the Oedo line may have brief micro-drops, but reconnection is automatic within seconds.
Shinkansen
Coverage is excellent on the Tokaido (Tokyo to Osaka) and Sanyo (Osaka to Hiroshima) lines. Brief drops in long tunnels on the Tohoku line (toward Sendai/Morioka) are normal. The eSIM reconnects on the other side.
Rural and mountain areas (Japanese Alps, interior Shikoku)
NTT Docomo has the best rural coverage in Japan. If you are hiking in the Japanese Alps (Kamikochi, Tateyama) or interior Shikoku, force network selection to Docomo.
At the airport (Narita, Haneda, Kansai)
Japan is one of the fastest countries for eSIM connection on landing. If you have no data within 2 minutes, it is a phone setting issue, not the network.
Still not working?
Prepare these three things and contact support:
Support typically identifies the cause in a single exchange.
FAQ
Why does my eSIM have no signal in Japan?
Most likely data roaming is not turned on for the eSIM line. Enable it in your mobile data settings. If you see signal bars but no data, also check that the eSIM is set as your data line.
What APN should I use for my eSIM in Japan?
None. The eSIM sets its own APN automatically. Do not enter an APN for NTT Docomo or any other local operator.
Do I need to enable roaming to use my eSIM in Japan?
Yes, it is required. Data roaming must be ON for the eSIM line. There is no extra charge. Roaming is already included in your plan.
My eSIM worked yesterday in Japan but not today. What do I do?
Check that your plan is not expired or used up. If it is still valid, toggle airplane mode (10 seconds on, then off). If that does not help, force network selection to NTT Docomo then switch back to automatic.
Do I need a pocket WiFi in Japan if I have an eSIM?
No. A travel eSIM uses the same 4G/5G networks as a pocket WiFi (same operators, same towers) without an extra device to charge, carry and return.
Do I need to set an APN? · Data roaming toggle fix · Japan eSIM guide · Japan coverage map · Drift Asia Help Center