Japan's Four Mobile Operators Restore Networks Within Two Days After Kumamoto Quake; Starlink Use Triples

Mobile phone networks in Kumamoto Prefecture were restored within about two days after the earthquake that struck on July 28. During the restoration, the four major mobile operators divided work by region and concentrated on repair operations, relying on an equipment-sharing mechanism established earlier to reduce the duration of service disruptions.

NTT DoCoMo and KDDI experienced communication failures immediately after the quake, while SoftBank and Rakuten also faced communication difficulties the following day after power outages left backup batteries depleted. More than 150 base stations were damaged, but the impact was kept relatively contained through measures such as securing detour routes. The Japan Roaming service played a key role in the rapid recovery, allowing operators to access other companies' available lines during disasters and enabling mutual supplementation across networks.

Satellite communications have entered practical use in disaster response compared with a decade ago. KDDI, NTT DoCoMo and SoftBank have adopted SpaceX's Starlink satellite service, which allows users to send and receive text messages even in no-signal areas as long as the sky is visible. NTT DoCoMo data show usage in the first week after the quake reached three times the level of the previous week. Rakuten Group is working with a US space startup to commercialize its own satellite communication service and has successfully conducted video calls in verification trials.