NTT Docomo Hit by Nationwide 5G Outage in Japan

Developing — last updated 5 November 2026 at 3:00 p.m. PKT.

NTT Docomo, one of Japan's largest mobile carriers, said on Thursday that its standalone 5G service was unstable across the country, leaving customers struggling to make calls, use mobile data and send text messages. The disruption began at around 11:18 a.m. local time and was still unresolved hours later, according to the company. It came on the same day Docomo suspended its online shop and customer portal after concluding that an outside party had probably gained unauthorised access to its servers — although the company said it was not yet clear whether the two incidents were connected.

The outage affected Docomo's 5G standalone service, known as 5G SA, a high-speed, high-capacity network used by a portion of its customers. Other 5G services and the carrier's 4G network were unaffected, the company said, and emergency calls continued to work. Customers on the affected service were advised to switch their phones to 4G in their network settings and then restart the handset or toggle airplane mode on and off.

Docomo said it was investigating the cause of the disruption and had found no signs that it was caused by a cyberattack. Services offered by other mobile providers that run on Docomo's network were also affected, according to Japan Today.

What happened

According to Kyodo News, Docomo said voice calls, data communications and text messaging on its 5G SA service had been unstable since around 11:18 a.m. on Thursday, 5 November. Jiji Press reported a similar start time of around 11:20 a.m. The problems were nationwide, rather than confined to one region.

The timing matters. The disruption struck in the middle of the working day in Japan, when mobile data underpins everything from payments and deliveries to business communications. A nationwide mobile outage can spread quickly beyond missed calls: corporate systems, logistics and payment terminals that rely on mobile connectivity can all feel the knock-on effects.

Docomo did not give a restoration time in its announcements. The company said only that it was investigating the cause and would provide further information as details became clear.

A second problem, hours earlier

Separately, and hours before the network problems began, Docomo suspended its online shop and its "My docomo" customer portal. The suspension began at around 1:05 a.m. on Thursday, leaving customers unable to sign up for mobile plans, check their bills or make contract changes.

The company said it had taken the services offline after determining that an outside party had likely gained unauthorised access to its servers. It was investigating whether any customer data had been leaked, according to Kyodo News. Jiji Press reported the same suspension, describing it as a precaution while the company examined whether its servers had experienced unauthorised access.

Docomo said it was unclear whether the suspected unauthorised access was linked to the mobile service disruption later in the morning. The two incidents have been treated as separate problems for now, and the company has not attributed either to a cyberattack.

What customers can do

For customers on the affected 5G SA service, Docomo suggested a workaround: switch the phone's network setting to 4G, then restart the handset or toggle airplane mode on and off. Because the company's other 5G services and its 4G network were unaffected, that switch should restore service for most affected users.

Emergency calls were not affected by the disruption, according to Kyodo News's updated report. Customers who need to use the suspended online services — signing up for a plan, checking a bill or changing a contract — will have to wait until Docomo restores the online shop and the My docomo portal, or use another channel such as a physical store.

Why it matters

Japan's mobile networks are among the most heavily used in the world, and Docomo is the country's largest carrier by subscribers. A nationwide disruption to even one slice of its network — the standalone 5G service — affects a large number of people and the businesses that depend on them.

The incident also lands at an awkward moment for the carrier. In October, Docomo disclosed that a system malfunction had stopped its "Area Mail" emergency earthquake alerts from reaching users in eastern Japan, after the Japan Meteorological Agency issued a bulletin that was later retracted. That failure was unrelated to Thursday's outage, but it means the company is facing fresh questions about the reliability of its systems only weeks later.

Regulators in Japan have taken a close interest in major telecom outages before. Rival carrier KDDI suffered a lengthy nationwide outage that left tens of millions of lines without service, and was told by the government to improve its operations. Docomo itself has faced regulatory scrutiny after past large-scale outages.

Time (JST)	Event
Around 1:05 a.m.	Docomo suspends its online shop and My docomo portal after concluding an outside party likely gained unauthorised access to its servers.
Around 11:18 a.m.	Voice calls, data and text messaging on the 5G standalone service become unstable nationwide.
Afternoon	Docomo says it is investigating the cause, has found no signs of a cyberattack behind the network disruption, and advises affected customers to switch to 4G.

Frequently asked questions

What exactly is affected?

Docomo's 5G standalone (5G SA) service. Voice calls, mobile data and text messaging on that service have been unstable since late morning on Thursday. The company's other 5G services, its 4G network and emergency calls are unaffected.

Is this a cyberattack?

Not according to what Docomo has said so far. The company said it had found no signs that the network disruption was caused by a cyberattack. The separate suspension of its online services was linked to suspected unauthorised access to its servers, and the company said it was unclear whether the two incidents were connected.

Has customer data been leaked?

That is not yet known. Docomo said it was investigating whether any data had been leaked after concluding that an outside party had likely gained unauthorised access to its servers.

What should affected customers do?

Switch to 4G in the phone's network settings, then restart the handset or toggle airplane mode on and off, as Docomo advised. Customers needing the online shop or My docomo portal will have to wait for those services to be restored.

When will service be fully restored?

Docomo has not given a restoration time for either the network disruption or the suspended online services.

What to watch next: Docomo's next update on the cause of the disruption and a restoration time, its findings on whether customer data was exposed in the suspected server intrusion, and any statement from Japan's communications ministry. If the outage drags on or the intrusion proves serious, expect regulators to ask the carrier for a formal report — as they have after past large-scale telecom failures in Japan.