• Japanese operator NTT Docomo is about to launch its satellite direct-to-device (D2D) service
• It is one of the initiatives of its space division, NTT C89 
• It is playing catch-up with rival KDDI, which has had its nationwide D2D service up and running for almost a year

NTT Docomo is to launch a satellite direct-to-device (D2D) service that “enables direct communication between satellites and smartphones in early 2026,” the Japanese operator has announced, with SpaceX’s Starlink as its low-earth orbit (LEO) satellite constellation partner. 

The service will enable any of its customers (consumer or enterprise) with certain 4G/LTE-compatible smartphones “to send and receive text messages and use compatible apps for data communication in areas where terrestrial base station communications have not been available until now, such as mountainous regions, remote islands and at sea, as well as in areas where terrestrial communications facilities have been damaged during disasters,” Docomo noted in this announcement (in Japanese). 

Docomo notes that terrestrial base stations currently enable mobile service delivery to 99% of the Japanese population, but “there are still areas where radio waves cannot reach due to geographical constraints. Furthermore, in the event of a large-scale disaster, such as an earthquake or typhoon, there is a non-negligible risk that terrestrial communications facilities will be cut off, leaving affected areas isolated… Through this service, Docomo aims to realise a network that allows users to connect anytime, anywhere and contribute to improving the safety and convenience of society,” the operator added, though it didn’t provide any details about tariffs or which smartphone models will be compatible with the service at launch. 

The move is one of the initiatives of NTT Group’s NTT C89 division, the space-focused unit that was launched in 2024. At that point, Starlink was not a partner, but the satellite operator now has a fleet of more than 650 ‘Direct to Cell’ LEO satellites, orbiting at 360km above the earth’s surface (compared with the 550km orbit of its 8,000-plus broadband service satellites), that have integrated cellular base station and antenna technology.

When Docomo launches its service, it will be playing catch-up with major domestic rival KDDI, which began its own collaboration with Starlink as long ago as 2023 and which launched a national D2D service called au Starlink in April last year.

And it will face competition too from SoftBank, which is also set to launch a D2D service in partnership with Starlink this year.

Japan’s other main mobile operator, Rakuten Mobile, is also set to launch its D2D service this year, though its satellite partner is AST SpaceMobile, in which Rakuten Group has long been an investor. 

- Ray Le Maistre, Editorial Director, TelecomTV