MobileNov 12, 2026, 1:01 AM UTC·1 min read

NTT Docomo 5G SA Outage Mostly Restored, Cause Still Unknown

NTT Docomo says most 5G SA subscribers are back online after a nationwide outage that began on November 11, but service was not fully restored and the cause is under investigation.

A smartphone showing no signal in front of a blurred Tokyo street, illustrating the NTT Docomo 5G SA network outage. — Image: ITmedia NEWS

NTT Docomo said on November 11 that service has been restored for most customers affected by a nationwide outage that began at around 10:34 a.m. that day. As of 4:30 p.m., however, the problem had not been fully resolved, and the company was still working on it.

The outage hit subscribers on "5G SA", the standalone mode that runs on dedicated 5G equipment only. Voice calls, data connections and SMS were difficult to use. According to Docomo, customers on other 5G and 4G services, MVNOs that use Docomo's network, and emergency calls were not affected.

Cause under investigation

Docomo has not identified the cause. As of 4:30 p.m., the company said it had found no signs of unauthorized access or evidence of a cyberattack. Users who still have trouble connecting are advised to restart their device or switch airplane mode on and then off again. Docomo updated this guidance during the day.

Second outage in a week

The incident follows another nationwide 5G SA outage on November 5. That one lasted about 14 hours, with service restored at around 1:20 a.m. on November 6. Docomo attributed it at the time to traffic concentrating on the switching equipment that handles 5G SA subscribers' communications, which could no longer keep up with processing.

Two disruptions affecting the same service within a week raise questions for 5G SA users about reliability, especially as the carrier has not yet said whether the two events are linked. Docomo is continuing its recovery work and investigation into what went wrong.

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