Japan Mobile Networks & Coverage Guide
Japanese mobile networks: what you need to know
Japan has four mobile networks. Three are excellent, one is a work in progress. Coverage across Tokyo and major cities is not a problem. Coverage in rural areas and mountains is where the differences start to matter.
NTT Docomo, the biggest and most reliable
NTT Docomo is the largest carrier in Japan with the widest coverage footprint. It’s the equivalent of AT&T in the US or Swisscom in Switzerland. Best coverage in rural areas, on bullet trains, and in mountain regions.
Most travel eSIMs that connect to “the best network” in Japan are using Docomo’s infrastructure.
- 4G: Near-universal coverage, including rural Japan
- 5G: Major cities (Tokyo, Osaka, Nagoya, Fukuoka)
- Best for: Travelers going outside major cities
KDDI au, excellent and neck-and-neck
KDDI (branded as “au”) is the second-largest carrier and practically tied with Docomo in urban coverage. In cities like Tokyo and Osaka, you won’t notice any difference. KDDI also has strong rural coverage, though Docomo edges it out in the most remote areas.
Nomad and several Airalo plans use KDDI au networks.
- 4G: Excellent nationwide
- 5G: Expanding in major metro areas
- Best for: Travelers staying mainly in cities and popular tourist areas
SoftBank, solid in cities
SoftBank is the third major carrier. Excellent in Tokyo, Osaka, Kyoto, and other major cities. Fine on main bullet train routes. A bit weaker than Docomo and KDDI in truly rural or mountainous areas, but for most tourists who stick to the standard itinerary, it’s perfectly adequate.
- 4G: Very good in urban areas, some gaps in remote regions
- 5G: Available in major cities
- Best for: City-focused trips
Rakuten Mobile, skip it
Rakuten is the newest carrier, still building out its network. They rely on roaming agreements with KDDI au to fill coverage gaps. As a tourist, there is no reason to choose Rakuten over the established three. You’d just be getting a less reliable version of KDDI’s network with extra complexity.
Which network does your eSIM use?
| Provider | Network(s) | Good for rural/mountains? |
|---|---|---|
| Ubigi | Varies (typically Docomo) | Yes |
| Nomad | KDDI au / SoftBank | Yes, in most areas |
| Holafly | Multiple carriers | Yes (multi-network) |
| Sakura Mobile | Major carriers | Yes |
| Mobal | NTT Docomo / SoftBank | Yes |
| Airalo | Varies by plan | Check before buying |
If your provider says "varies by plan," check which network you'll be on before purchasing. For trips that include rural Japan, Hokkaido, or the Japanese Alps, prioritize plans on Docomo or KDDI au.
Coverage by area
| Area | Docomo | KDDI au | SoftBank |
|---|---|---|---|
| Tokyo (23 wards) | Excellent | Excellent | Excellent |
| Osaka / Kyoto | Excellent | Excellent | Excellent |
| Hiroshima / Fukuoka | Excellent | Excellent | Good |
| Hokkaido (cities) | Excellent | Good | Good |
| Hokkaido (rural) | Good | Fair | Fair |
| Okinawa | Excellent | Good | Good |
| Japanese Alps / Hakone | Good | Good | Fair |
| Bullet trains (Shinkansen) | Excellent | Good | Good |
| Tokyo Metro (underground) | Good | Good | Good |
| Rural countryside | Good | Fair | Fair |
In Tokyo, all three networks are effectively identical. The differences only emerge when you leave the major metros.
What speeds to expect
- 4G in Tokyo: 30-100 Mbit/s on all networks
- 5G in Tokyo (where available): 200-500+ Mbit/s
- 4G on bullet trains: 10-50 Mbit/s (drops in tunnels)
- 4G in rural areas: 10-30 Mbit/s on Docomo, variable on others
- Tokyo Metro (underground): 5-30 Mbit/s (most stations have coverage)
Japan has some of the best mobile infrastructure in the world. In Tokyo, you'll get fast, reliable data on any of the three major networks. Speed differences between carriers are negligible for normal use.
Underground coverage in Tokyo
The Tokyo Metro and other subway systems have mobile coverage in stations and increasingly in tunnels between stations. You’ll have signal while waiting on the platform and during most of the ride. Some older tunnel sections still have dead spots, but these are getting shorter every year.
Don’t count on perfect underground connectivity for video calls, but messaging, maps, and social media work fine.
The bottom line
- Staying in Tokyo / major cities? Any network works. Pick based on price.
- Going to rural Japan, Hokkaido, or mountains? Prioritize Docomo-based plans.
- Taking the bullet train? All three work, Docomo is most consistent.
- Considering Rakuten? Don’t.