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BreachRecord

Marriott International, Inc. Data Breach (November 2018): What Was Exposed and What To Do

Last updated Oct 20, 2026 · Based on 2 official filings · See sources

According to the notice filed with the California Attorney General on Nov 30, 2018, Marriott International, Inc. reported a data breach. It was also reported to the Maine Attorney General. People affected: 500,000,000 people (official total in the Maine Attorney General filing, filed Dec 19, 2018).

Key facts

From 2 official filings
Organization
Marriott International, Inc.
Source: California Attorney General, filed Nov 30, 2018
People affected
500,000,000
Official total in the Maine Attorney General filing, filed Dec 19, 2018
Source: Maine Attorney General, filed Dec 19, 2018
Incident dates
Sep 10, 2018
Source: California Attorney General, filed Nov 30, 2018
Discovered Sep 8, 2018
Source: Maine Attorney General, filed Dec 19, 2018
Notice dates
Letters dated Nov 30, 2018
Source: Maine Attorney General, filed Dec 19, 2018
First filed Nov 30, 2018; latest filing Dec 19, 2018
Information exposed
  • Financial account number
  • Payment card
Source: Maine AG, Dec 19, 2018
Filed with
Free credit monitoring
Offered
Duration: 12 months; Provider: Kroll
Source: Maine Attorney General, filed Dec 19, 2018

What to do now

Steps chosen from the information listed in the official filings. Your own letter may list more.

  1. Marriott International, Inc. offered free credit monitoring. Use the enrollment code printed in your letter. Never share that code with anyone who contacts you.

    Source: Maine Attorney General, filed Dec 19, 2018

  2. Call the number on the back of your card, ask whether it should be replaced, and check recent charges for anything you do not recognize.

  3. Review recent transactions, ask about account alerts, and ask whether a new account number is recommended.

  4. Scammers often contact people after a breach, pretending to be the organization, a bank or a government agency. Do not give your Social Security number, passwords or codes to anyone who contacts you first.

  5. You can get free credit reports from all three bureaus at AnnualCreditReport.com, the official site.

  6. The Federal Trade Commission's IdentityTheft.gov gives you a personal recovery plan.

Is the letter real?

Letters usually list a phone number for questions. We could not find an official copy of the letter, so check that the organization named in your letter appears in the official filings listed below before you call.

Never give your Social Security number, bank details or passwords to someone who contacts you first.

Timeline

  1. Organization discovered the incident source
  2. Incident began (earliest date reported) source
  3. Notice letters dated source
  4. Reported to California AG source
  5. Reported to Maine AG source

Sources

  1. California Attorney General Notice filed Nov 30, 2018
    Filed as “Marriott International, Inc.”
  2. Maine Attorney General Notice filed Dec 19, 2018
    Filed as “Marriott International, Inc.” · total 500,000,000
    The link opens the Maine Attorney General's archive of notices (2012–2020).

Last updated Oct 20, 2026. Our summaries are written in our own words from the official filings above. Spotted an error? Report a correction.