Docomo’s nationwide 5G SA disruption nears three hours, with no recovery estimate

NTT Docomo was still working to restore service at 1:30 p.m. Japan Standard Time, two hours and 56 minutes after the disruption began at 10:34 a.m. The carrier had not identified the cause or provided an estimated recovery time. For affected customers, its immediate advice was to try connecting through 4G instead.⁠44

The limits of that advice matter. Switching networks may get a customer’s calls, messages and data working again; it does not mean Docomo has repaired the underlying fault. And the 176 minutes between the onset and the afternoon bulletin measure how long the incident remained unresolved at that checkpoint—not its final duration or every subscriber’s downtime.⁠44

Docomo identified subscribers to its 5G SA option as the affected group. It explicitly excluded other 5G customers who had not subscribed to that option, people using 4G, and mobile virtual network operators—other providers using Docomo’s network. The company did not give an affected-customer total. “Nationwide” describes the geographic reach of the disruption, not a count of people who lost service.⁠44

SA stands for standalone. Docomo’s service explanation says it uses dedicated 5G equipment, whereas ordinary non-standalone 5G, or NSA, combines 5G and 4G equipment. Standalone service is a distinct option: owning a 5G-capable phone does not by itself place someone in the affected subscriber group.⁠39

That distinction helps explain why customers on the same carrier could have different experiences during the incident. It establishes which service was impaired, however, not which component failed. Docomo’s fourth incident notice still listed the cause as under investigation.⁠44

For affected subscribers, the disruption reached three basic ways of contacting someone: speaking, sending a text and getting online. Some phones could show a no-service indication, the carrier warned. But its description was difficulty using those functions, not a finding that every affected phone had completely lost all three. The same notice explicitly said emergency calls were unaffected.⁠44

Docomo’s instruction has a clear order: first select 4G in the phone’s network settings. Then either restart the phone or turn airplane mode on and off. A restart and an airplane-mode cycle are alternatives after selecting 4G; the instruction does not require doing both. The company says this procedure may make voice calls, mobile data and SMS usable again.⁠44

The word may is doing real work. This is a possible route around the impaired standalone service, not a guaranteed fix. A customer who reconnects through 4G may regain access while restoration work continues. Conversely, an unsuccessful attempt does not establish anything new about the cause of the network problem. The advice is directed at affected subscribers, not a reason for customers whose service is working normally to change their settings.⁠44

For assistance, Docomo lists 113 from its mobile phones and 0120-800-000 from other phones. Its third incident notice also lists the Docomo assistance chatbot, accessible from a smartphone or computer. The carrier describes those support channels as available 24 hours a day, year-round. Their availability is not a promise that an impaired mobile connection will successfully reach them.⁠29

The repeated bulletins documented continuing impairment, not a recovery. At the latest verified checkpoint of 1:30 p.m. JST, Docomo had supplied neither a restoration estimate nor an affected-customer count. The notices therefore support a precise account of the service boundary and the temporary workaround, but not a claim about how many people were disconnected or when normal service would return.⁠44

For customers, those are two different kinds of progress to watch: whether they can regain access through 4G now, and whether Docomo confirms that standalone service itself has been restored. Success with the first is useful. It is not evidence of the second.