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Using an eSIM in Japan: what to know first
Japan has three major networks with very different coverage in the mountains and on the subway. Picking the right one matters more than picking more gigabytes.
Cập nhật 15/07/2026
Japan has some of the best mobile infrastructure in the world, but a few things still confuse first-time visitors.
Three carriers and what actually differs
| Carrier | Strongest in | Note |
|---|---|---|
| NTT Docomo | Mountains, countryside, Hokkaido | Widest coverage in Japan |
| SoftBank | Big cities, subway | Fast in Tokyo and Osaka |
| KDDI au | Balanced | Reliable along Shinkansen lines |
For a Tokyo–Kyoto–Osaka itinerary any carrier is fine. For Hokkaido, the Nagano mountains, or villages like Shirakawa-go, prefer a plan running on Docomo.
Subways and the Shinkansen
Most Tokyo and Osaka subway stations have signal, tunnels included. The Shinkansen is different: long mountain stretches drop out, especially Tokyo–Kanazawa. That is normal, not an eSIM fault.
Commonly misunderstood
- Travel eSIMs in Japan are data-only — no Japanese number for phoning restaurant bookings. Use apps or ask your hotel.
- Public Wi-Fi is common but usually needs email registration and cuts out after 15–60 minutes. Do not rely on it.
- 5G covers big-city centres well; elsewhere it is 4G — still faster than most 4G in Southeast Asia.