Definition
au is a commercial brand of mobile telecommunications services operated by KDDI Corporation, a major Japanese telecommunications company. The brand provides cellular voice, data, and related mobile services to consumer and corporate customers in Japan.
Overview
The au brand was introduced in 2000 as part of KDDI’s effort to consolidate its mobile operations, which had previously been provided under separate entities such as DDI, IDO, and KDDI Mobile. Since its launch, au has positioned itself as a nationwide carrier offering a full suite of mobile technologies, including 3G (WCDMA), 4G LTE, and 5G NR networks. The service is marketed alongside a range of handsets, including flagship smartphones from global manufacturers, and is bundled with value‑added services such as mobile payment, video streaming, and cloud storage. As of the early 2020s, KDDI (through the au brand) is the second‑largest mobile network operator in Japan, trailing only NTT Docomo, and competes closely with SoftBank.
Etymology / Origin
The name “au” is derived from the phrase “access you,” reflecting the brand’s focus on providing users with seamless access to communication services. The stylisation in lowercase letters is a deliberate branding choice intended to convey a modern and approachable image.
Characteristics
| Characteristic | Details |
|---|---|
| Parent company | KDDI Corporation (formerly KDDI Holdings) |
| Launch year | 2000 |
| Network technologies | 3G (WCDMA), 4G LTE, 5G NR (sub‑6 GHz and mmWave) |
| Service offerings | Voice calls, SMS/MMS, mobile broadband, mobile‑payment platforms (e.g., au PAY), streaming services, device financing, and IoT solutions |
| Coverage | Nationwide, with extensive urban and rural cell site density; participates in shared‑infrastructure agreements to improve rural coverage |
| Market position | Second‑largest mobile carrier in Japan, holding roughly 30 % of the subscriber base (exact share varies by reporting period) |
| Brand extensions | au by KDDI (corporate branding), au Hikari (fiber broadband), au SmartPass (digital content subscription) |
| Key competitors | NTT Docomo, SoftBank, Rakuten Mobile |
Related Topics
- KDDI Corporation – The parent company that owns and operates the au brand, also providing fixed‑line, broadband, and international communication services.
- Japanese mobile telecommunications market – The competitive landscape encompassing major carriers (Docomo, SoftBank, Rakuten) and regulatory frameworks overseen by the Ministry of Internal Affairs and Communications.
- 5G deployment in Japan – National initiatives and spectrum allocations that have enabled carriers like au to launch commercial 5G services.
- Mobile payment systems – au PAY and related digital wallet services, part of a broader trend of mobile‑first financial solutions in Japan.
- IoT (Internet of Things) services – au’s offerings for connected devices, including smart home and automotive applications.
Accurate information is not confirmed for any specific market‑share figures beyond publicly reported estimates.