California Statute of Limitations for Defamation:
Generally one year
The statute of limitations for defamation in California is generally one year from the date of the publication of the defamatory statement pursuant to California Code of Civil Procedure §340(c).
If the statement was made in a way that was not public or discoverable by the plaintiff, then the statute of limitations can be extended to begin from the date that the victim discovers or reasonably should have discovered the publication of the defamatory statement.
For statements made in public locations on the internet, the statute of limitations is generally one year from the date of the posting, regardless of when the victim discovered the posting.