The key facts

  • The NTT Docomo outage affected voice calls, mobile data and SMS across Japan from around 11:18 local time
  • The company advised customers to switch network settings to 4G and is checking whether the problems affected emergency calls
  • Separately, the online store and My Docomo portal were suspended due to likely unauthorized access; a link to the network outage has not been confirmed

A nationwide network outage

Japan's largest mobile carrier NTT Docomo faced unstable service across the country on Thursday, November 5. According to company figures cited by the Kyodo news agency, the problems began at around 11:18 local time (02:18 GMT) and affected voice calls, mobile internet and text messages. Users across Japan reported connectivity issues.

What is known about the causes and measures

The carrier said it is investigating the cause of the outage and has no timeline for restoring services. Customers were advised to switch their mobile network settings to 4G while the disruptions continue. Since the outage occurred at the Docomo network level, it also affected the services of other operators using its infrastructure. The company is also checking whether the problems affected the ability to make emergency calls.

A separate server access incident

In addition to the network outage, Docomo suspended its online store and the My Docomo customer portal after concluding that a third party had likely gained unauthorized access to its servers. The suspension, which began early Wednesday morning, left customers unable to sign up for mobile plans, check bills or make changes to their contracts. The carrier stressed that it is not yet clear whether the suspected unauthorized access is related to the nationwide mobile outage.