KDDI and Okinawa Cellular have launched a groundbreaking service called 'au Starlink Direct' on April 10, 2025, marking Japan's first direct communication service between smartphones and satellites. This innovative service enables users to communicate via satellite even in areas where traditional signals are unavailable, such as mountainous regions, remote islands, and at sea.
The service utilizes SpaceX's low-Earth orbit satellite broadband, known as Starlink, to provide coverage across all of Japan, including its territorial waters. Currently, the service is free of charge for au users, with no prior application required. This means that users can send and receive messages, including SMS, RCS, and iMessage, and also share their current location information. Additionally, they can receive vital emergency alerts, such as earthquake warnings and tsunami notifications.
According to KDDI, the service aims to fill a significant gap in communication coverage. While the company's population coverage rate exceeds 99.9%, the geographical terrain of Japan limits the area coverage rate to about 60%. With 'au Starlink Direct', KDDI hopes to connect users in the remaining 40% of the area where reliable communication has been challenging to establish.
The compatible devices for this service include the latest iPhone models (14, 15, and 16 series) and a variety of Android smartphones, including all Xperia models released since 2023 and nearly all Galaxy models launched since 2022. In total, around 50 smartphone models are supported. When a compatible smartphone enters an area without service, it will automatically connect to the Starlink satellite if the sky is visible, allowing users to send and receive messages. A notification will appear in the messaging app indicating that satellite communication is available.
This service is particularly beneficial for individuals in emergency situations. For example, if someone is stranded while hiking in a remote area, they can send messages to family or friends and share their location, which could be crucial for rescue operations. Matsuda Hiromichi, President and CEO of KDDI, emphasized that making the service free enhances the sense of security for au users. He stated, "We want this to be seen as one of the values of our main brand, rather than merely a revenue-generating service."
In the context of increasing competition in the mobile phone market, KDDI's satellite communication service is poised to be a significant differentiator. Other carriers are also exploring similar technologies; for instance, Rakuten Mobile is expected to launch its own direct communication service between smartphones and satellites using AST SpaceMobile satellites in 2026. Meanwhile, NTT Docomo and SoftBank are focusing on expanding mobile coverage using High Altitude Platform Stations (HAPS), with Docomo aiming for commercialization by 2026.
Gwynne Shotwell, President and COO of SpaceX, expressed enthusiasm about the collaboration with KDDI, noting that this service represents a first in Asia and a pioneering effort worldwide. She remarked, "We are very pleased to realize the direct communication service between satellites and smartphones in Japan with KDDI. 'au Starlink Direct' will allow connectivity anywhere in Japan, potentially saving lives during emergencies."
The introduction of 'au Starlink Direct' follows successful testing conducted in October 2024 on Kume Island, Okinawa, where KDDI first demonstrated direct communication between Starlink satellites and smartphones. Initially, the service was limited to Android devices, but support for iPhones was secured just in time for the official launch.
As KDDI continues to expand its service offerings, the company is also actively working on enhancing communication infrastructure in hard-to-reach areas by utilizing mobile base stations and satellite technology. This initiative aims to provide a seamless communication experience for users, whether in their daily lives or during extraordinary circumstances.
With the launch of 'au Starlink Direct', KDDI is not only setting a precedent in Japan but is also contributing to the global advancements in satellite communication technology. This service promises to bridge the communication gap in underserved regions, providing a vital lifeline for individuals in emergencies and enhancing connectivity across the nation.
As the landscape of mobile communications evolves, the introduction of satellite connectivity could redefine how users interact with their devices, especially in areas where traditional networks fall short. With 'au Starlink Direct', KDDI is paving the way for a more connected future, where the sky is not the limit but rather a gateway to endless possibilities.
