NTT Docomo Confirms Customer Data Leak After Online Access

NTT Docomo confirmed a customer data leak linked to unauthorized access to Docomo Online Shop and My docomo, putting the estimated number of affected records at up to about 300,000 in a notice dated November 6, 2026. Emergency maintenance remained in progress on both services that day, while the company investigated the extent of the incident.

A more specific estimate presented by Docomo at its November 6 briefing counted 294,839 affected records on a line basis. That figure included 204,157 lines under individual contracts, according to ITmedia. The company’s notice said the final number of affected records and the full scope of the leak were still under investigation.

According to the notice, the exposed data included contract and service-plan information, mobile telephone numbers, identification-document numbers, names, addresses, other contact information, and details of birth or age. Docomo also identified additional categories present in some affected records: banking and financial-institution details, employer or corporate information, and data associated with its child-rearing support program. Some records contained names and contact information for legal or procedural representatives.

In statements reported by Jiji Press, Docomo president Yoshiaki Maeda said records belonging to former subscribers were among the affected information, but credit-card data had not been compromised. Maeda also said Docomo planned compensation for affected people, with the recipients still to be determined.

Docomo said it first detected the external access on November 4, 2026. Procedures through the two services were halted at approximately 1:05 a.m. on November 5. In its November 6 update, the company confirmed that no new information leakage had been identified and said its investigation also covered the route used to gain access.

For customers, Docomo said the disclosed information could be used by people impersonating the company or related parties through telephone calls, email or text messages. Its notice advised customers to avoid opening suspicious attachments or links and not to supply personal information, passwords or credit-card details in response to such communications.

* This article is based on publicly available information at the time of writing.