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NTT Docomo data breach

Was I affected?

NTT Docomo confirmed a breach affecting about 300,000 people, exposing names, addresses, dates of birth and phone numbers. You may be affected if you are a current or former NTT Docomo mobile customer in Japan; Docomo says it will decide which customers receive compensation later.

NTT Docomo breach facts
AnnouncedNov 5, 2026
When it happenedDetected November 4, 2026
CountryJapan
People affected300,000
Data exposedNames, Addresses, Dates of birth, Phone numbers, Bank or financial details and Other details
StatusConfirmed by the company or a regulator filing

What happened

Japan's largest mobile carrier NTT Docomo said it detected unauthorized access on November 4, 2026 and shut down My docomo and its online shop early the next day. Up to about 300,000 sets of customer information were taken, including names, addresses, dates of birth, phone numbers, ID document numbers and plan details, plus bank account numbers and account holder names for some customers; former subscribers are included. Docomo says credit card information was not leaked and it plans to pay compensation, with the scope still to be decided.

What should I do?

  1. Watch the bank account linked to your Docomo bill for withdrawals or debits you don't recognize, and tell your bank right away if you see any.
  2. Don't give card numbers, passwords or security codes in reply to emails, texts or calls that claim to be from Docomo; Docomo has warned of suspicious messages.
  3. When My docomo is back, sign in by typing the address yourself or using the official app, and change your d ACCOUNT password if you reuse it elsewhere.
  4. Be alert to scams that quote your plan details or ID number to sound official, and check Docomo's official site for its notice and compensation details.
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