Starlink gives KDDI nationwide D2C coverage

• KDDI has been working with Elon Musk’s Starlink since 2023 to develop satellite direct-to-cell (D2C) services
• Following successful trials, KDDI is now offering nationwide geographic coverage of Japan, for mobile messaging services initially, for regular smartphone users via Starlink’s constellation
• The service, offered free to KDDI’s Au mobile service customers, enables the telco to cover the 40% of Japan’s land mass that it cannot reach via its terrestrial cellular network

Following extensive tests and trials with low-earth orbit (LEO) constellation operator Starlink, Japan’s KDDI is now offering geographic nationwide mobile messaging coverage to its customers via direct-to-cell (D2C) satellite connections and claims it is the first telco in the country to offer such a service. 

KDDI has been developing the offer with Starlink, part of Elon Musk’s SpaceX company, since 2023 and in October last year completed a successful trial of the service, which enables regular smartphones to connect directly with the LEO satellites. 

Now KDDI says it, together with its subsidiary Okinawa Cellular, is providing full nationwide coverage for text messaging, earthquake alerts and location information updates to both companies’ mobile customers for free (though the operator notes that it will advise its customers in advance as and when charges will be applied to the service). In addition, Android users can send simple text message questions and receive responses from Google’s Gemini generative AI (GenAI) assistant.

The satellite-to-smartphone service, dubbed Au Starlink Direct (Au is KDDI’s mobile service brand), provides at least some communications service coverage to the telco’s customers in the 40% of Japan that cannot be reached by its terrestrial cellular network: The service is available on all of Japan’s islands and surrounding territorial waters as long as the user can see the sky.

KDDI says 50 Android and iPhone smartphone models (those that support satellite mode) can access the service as of 10 April. 

“I’m very excited to bring direct-to-cell phone connectivity to Japan through KDDI, the first in Asia and one of the first in the world,” stated Gwynne Shotwell, president and COO of SpaceX, in this announcement. “Both Starlink and direct-to-cell are game-changing technologies, making connecting the unconnected simple and bringing potentially life-saving capability to the people of Japan for disaster and other emergency responses,” she added. (It’s worth noting that Starlink helped One New Zealand to launch a nationwide D2C service late last year.)

KDDI may be first with a nationwide D2C service in Japan, but its rivals are all working on the same kind of offerings. 

NTT Group, including its mobile company NTT Docomo, has teamed up with Amazon’s Project Kuiper for the provision of various satellite services across Japan – see Amazon lands LEO satellite deal with NTT Docomo.    

Kuiper was due to launch its first satellites into orbit this week, but it had to be postponed due to adverse weather conditions: The next launch window has been set for Monday 14 April.  

In addition, NTT Docomo is testing other ways to provide an alternative to terrestrial mobile network coverage by exploring the potential of high altitude platform station (HAPS) services – see Japanese firms demo sky-high 5G.

SoftBank is also taking the HAPS route as part of its non-terrestrial network (NTN) plans, but its approach covers multiple bases. 

Three years ago, the Japanese multinational company introduced its own ‘concept’ of an NTN to “provide connectivity from space and the stratosphere”. The broader NTN plan includes collaboration with geostationary satellite operator Skylo Technologies for narrowband IoT (NB-IoT) services and Eutelsat/OneWeb for LEO-enabled data connectivity, but it also includes SoftBank’s own HAPS, a solar-powered “base station in the stratosphere” developed by its subsidiary HAPSMobile Inc. 

And in September 2024, SoftBank and US-headquartered Intelsat signed a “landmark collaboration” to build a single “ubiquitous network” to enable “seamless 5G connections” between terrestrial mobile networks and satellites so people (and things) can stay connected “anywhere in the world” with one device and one account – see SoftBank, Intelsat hatch ‘ubiquitous’ 5G plan.

Rakuten Mobile, meanwhile, has teamed up with AST SpaceMobile, which is focused on providing direct-to-cell services in partnership with multiple mobile operators around the world. The greenfield network operator’s parent company, Rakuten Group, has been an investor in AST SpaceMobile since 2020. Rakuten Mobile announced early last year that it plans to launch a satellite-to-smartphone service in 2026 using AST SpaceMobile’s LEO satellites, the first of which were launched into orbit last September. 

- Ray Le Maistre, Editorial Director, TelecomTV