Case file: T-Mobile USA
Every government filing on this incident, the dates as stated, and the days to notice against each state's statute. Built from the records on Nov 9, 2026, agency link on every row. Not legal advice.
The incident
- Breach window
- Jul 22, 2021
- Discovered
- Aug 17, 2021, as stated in the California letter
- State and federal records
- 2 filings, Aug 25, 2021 to Aug 27, 2021
- Residents counted
- No state publishes a resident count for this incident
- Everyone affected
- No filing gives a total
- Information exposed
- Social Security number, Financial / bank account, Usernames / passwords, Phone number, Postal address
- Offered to those affected
- No monitoring offer found in the letters we read
- Third party named
- No
- Days to notice
- Within the statutory period in all 2 states that set one, counted from discovery to each state's first record
- Prior incidents
- 1 earlier incident on record for this organization
The letter: "What happened: Log in (https://www.t-mobile.com) 8/19/2021 Our Response to the Data Breach (Aug 2021) | T-Mobile https://www.t-mobile.com/brand/data-breach-2021?icid=MGPO_TMO_P_21DTASECRT_8SZBD38SJT3BHWAY26101 2/5 On August 17, 2021,..."
Filings
| Agency | Record date | People | In total | Days to notice | Links |
|---|---|---|---|---|---|
| Oregon Oregon DOJ | Aug 27, 2021 | Not published | 10 days, statute 45 days | Record | |
| California California AG | Aug 25, 2021 | Not published | 8 days, statute 30 days | Letter Record |
People is the count the filing gives, residents of the state unless marked total. Days to notice runs from the discovery date the letter states, or from the end of the breach window when no letter states one, to the date on the state's first record of the incident. "Over" marks a count past the days the state's statute allows for notice to residents. The statute's trigger is a question of fact, the days are arithmetic.
Notice timing, state by state
- 10 days from discovery (Aug 17, 2021) to the Oregon record (Aug 27, 2021). Statute: 45 days from discovery or notification of the breach (ORS 646A.604).
- 8 days from discovery (Aug 17, 2021) to the California record (Aug 25, 2021). Statute: 30 days from discovery or notification of the breach (Cal. Civ. Code § 1798.82).
The statutes
- Oregon: 45 days to notify residents from discovery or notification of the breach, ORS 646A.604. Attorney General when more than 250 Oregon residents are affected, with the consumer notice.
- California: 30 days to notify residents from discovery or notification of the breach, Cal. Civ. Code § 1798.82. Sample notice to the Attorney General when more than 500 Californians are notified, within 15 days of the consumer notice (effective 2026).
Prior incidents by T-Mobile USA
| Records | Breach window | Filed with | People |
|---|---|---|---|
| Oct 1, 2015 | Sep 14, 2015 | California | n/a |
Filings more than six months apart are shown as separate incidents.
Sources and method
Records as published by Oregon DOJ, California AG. Letter facts (discovery date, monitoring, third party) are read from the consumer letter the agency posted, 1 letter read for this incident, and quoted so you can check them. Texas and HHS publish no letters. First-seen times on each record page. Spot an error? Email support@breachtally.com with this page link.