Japan has four companies that run their own mobile networks: NTT Docomo, KDDI (au), SoftBank and Rakuten Mobile. Almost every phone plan, prepaid SIM or travel eSIM sold in Japan runs on one of these four networks, even when the brand on the box is different. This page sets out how they compare on market share, spectrum, sub-brands and network history, using figures from Japan's Ministry of Internal Affairs and Communications (MIC) and the carriers themselves.
Last checked: 8 November 2026. Figures are dated individually below.
The four network operators at a glance
| NTT Docomo | KDDI (au) | SoftBank | Rakuten Mobile | |
|---|---|---|---|---|
| Share of mobile contracts, end of 2025 | 33.0% | 26.3% | 19.0% | 3.5% |
| Share including lines wholesaled to MVNOs | 39.4% | 31.4% | 24.6% | 4.4% |
| Own brands | docomo, ahamo | au, UQ mobile, povo | SoftBank, Y!mobile, LINEMO | Rakuten Mobile |
| 3G network | Ended 31 March 2026 | Ended 31 March 2022 | Ended 2024 | Never operated 3G |
Share figures are MIC's, for mobile contracts (mobile phones, PHS and BWA) after adjusting for transactions within each group, as of 31 December 2025. MVNOs held the remaining 18.0% of contracts.
How to read the market share
MVNOs (mobile virtual network operators) are brands that rent capacity on one of the four networks instead of building their own. The second share row adds the lines each operator supplies to MVNOs, which shows how much traffic actually rides on each network:
- Docomo is the largest network on both measures and the most common host for MVNOs.
- KDDI is second, and its numbers include the UQ mobile and povo brands.
- SoftBank is third, including Y!mobile and LINEMO.
- Rakuten Mobile is the newest operator. It launched full commercial service in April 2020 and announced on 25 September 2026 that it had passed 11 million lines (a total that includes MVNO, MVNE and business-continuity lines).
Spectrum held by each operator
Which frequency bands an operator holds decides where its signal reaches and which phones work well on it. Low bands (700 to 900 MHz) travel further and get into buildings more easily; higher bands carry more data over shorter distances.
| Band (MHz/GHz) | LTE / 5G band number | Docomo | KDDI group | SoftBank group | Rakuten |
|---|---|---|---|---|---|
| 700 MHz | B28 | Yes | Yes | Yes | Yes (narrow) |
| 800 MHz | B19 (Docomo), B18/B26 (KDDI) | Yes | Yes | ||
| 900 MHz | B8 | Yes | |||
| 1.5 GHz | B21 (Docomo), B11 (KDDI, SoftBank) | Yes | Yes | Yes | |
| 1.7 GHz | B3 | Yes (Tokyo, Nagoya, Osaka only) | Yes | Yes | Yes |
| 2 GHz | B1 | Yes | Yes | Yes | |
| 2.5 GHz | B41 | Yes (UQ) | Yes (Wireless City Planning) | ||
| 3.4 to 3.5 GHz | B42 | Yes | Yes | Yes | |
| 3.7 / 4.0 GHz | n77 / n78 (5G) | Yes | Yes | Yes | Yes |
| 4.5 / 4.9 GHz | n79 (5G) | 4.5 GHz | 4.9 GHz | ||
| 28 GHz | n257 (5G mmWave) | Yes | Yes | Yes | Yes |
Holdings are from MIC's survey of mobile spectrum use (FY2025). The KDDI group includes Okinawa Cellular and UQ Communications; the SoftBank group includes Wireless City Planning. Band numbers are the standard 3GPP mappings for each frequency range.
Two things stand out:
- Rakuten has much less low-band spectrum. It received a small 700 MHz allocation in October 2023 and otherwise relies on 1.7 GHz (B3) plus 5G bands. To fill gaps, it has used roaming on KDDI's network. In August 2026, KDDI said the existing roaming agreement would end in September 2026, with any continuation limited to some rural areas.
- Each older operator has its own "800 or 900 MHz" band. Docomo uses B19, KDDI uses B18/B26 and SoftBank uses B8. Phones built for other markets do not always support B19 or B18/B26, which can mean weaker coverage in the countryside and inside buildings even when the phone works fine in cities.
Japan no longer has any 3G network
All three original operators have switched off 3G:
- KDDI (au) ended 3G on 31 March 2022.
- SoftBank ended 3G in 2024; the last areas, in Ishikawa Prefecture, closed on 31 July 2024 after an extension following the Noto Peninsula earthquake.
- Docomo ended its FOMA 3G service and i-mode on 31 March 2026.
Rakuten Mobile launched on 4G and never ran 3G. In practice, a phone now needs 4G (and VoLTE for voice calls) to work in Japan.
What this means if you are visiting or moving to Japan
- Your SIM or eSIM brand is not your network. A travel eSIM, a prepaid SIM from a vending machine or a cheap MVNO plan will be riding on Docomo, KDDI, SoftBank or Rakuten. Check which one the plan uses.
- Check your phone's bands. B1, B3 and B28 are used by most operators and are widely supported. Support for B19 (Docomo) or B18/B26 (KDDI) improves coverage outside big cities on those networks.
- Your phone must be unlocked to accept a Japanese SIM or eSIM.
- For short trips, a data-only eSIM on a major network is usually the simplest option. For long stays, plans with a Japanese phone number generally need a residence card. Our guide to choosing between prepaid and monthly SIMs for your first year covers that decision.
If you are arriving soon, see where to buy a SIM or rent Wi-Fi in our Narita and Haneda airport guide, or browse shibaSIM's Japan eSIM plans.
Sources
- Ministry of Internal Affairs and Communications, White Paper on Information and Communications 2026: subscription status of voice services (market share as of end of December 2025)
- Ministry of Internal Affairs and Communications, FY2025 survey of radio spectrum use for mobile phones and nationwide BWA
- Ministry of Internal Affairs and Communications, FY2024 survey results: spectrum allocation status (700 MHz allocation to Rakuten Mobile, October 2023)
- NTT Docomo, End of FOMA and i-mode services
- Rakuten Group, Rakuten Mobile surpasses 10 million subscribers and 11 million lines report (Sumaho Info)
- Light Reading, Rakuten faces surge in 4G, 5G costs as KDDI cuts it off (11 August 2026)
- Cloud News, Japan turns off its last 3G network (KDDI and SoftBank 3G end dates)
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