Japan Post Data Breach History

This page tracks the Japan Post data breach history and cybersecurity incidents affecting Japan Post (Japan). BreachHistory currently indexes 1 publicly disclosed or catalogued incident spanning 2026, with approximately 600 records reported as exposed across all indexed events. These totals may include overlapping datasets or third-party estimates and should not be interpreted as unique affected users.

The Japan Post breach timeline includes major data breaches, cyber attacks, data leaks, credential exposures, API abuse, and other security incidents. Each incident provides details on the estimated records exposed, attack method, affected data types, and supporting public sources. Currently, 0 incidents are company-confirmed.

Largest Japan Post Data Breaches

The largest indexed incidents include the 2026 Japan Post — international inquiry web; ~600 records viewable. Record counts originating from threat actors or leak sites should be treated as estimates unless confirmed by Japan Post or a regulator. Below is the list of large data breaches:

• 2026 2026 Japan Post — international inquiry web; ~600 records viewable — about 600 records exposed · Catalogued incident

What Information Was Exposed?

Depending on the incident, exposed data may include email addresses, phone numbers, names, physical addresses, and other personal information (PII). The exact data varies between incidents, so review each breach page before assuming your information was affected.

Japan Post Data Breach 2026

At the time of this update, BreachHistory catalogues 1 2026 incident related to Japan Post. Most recent entry: 2026 Japan Post — international inquiry web; ~600 records viewable. New incidents are added as official disclosures, regulatory filings, or credible cybersecurity reports become available.

What To Do If You Were Affected

If you believe your account may have been involved in a Japan Post data breach, change any reused passwords, enable multi-factor authentication (MFA), monitor your account for suspicious activity, and be cautious of phishing emails or fake breach notifications.

This Japan Post breach history is maintained by BreachHistory using public disclosures, regulatory filings, security research, and clearly labelled third-party claims. For the complete breach timeline, records exposed, incident details, and AI Breach Risk Score, explore the sections on this page.