If a voted mail ballot is returned after a voter has already voted at the Registrar of Voters office, an early vote site, or a polling place, the ballot sorter recognizes and rejects the second ballot. If a voter attempts to vote in person after returning a voted mail ballot, election workers will check-in the voter using an electronic roster (or Poll Pad) that will identify whether the voter has already voted in the election. If the voter states he or she has not voted in this election, the voter may vote a provisional ballot, and County staff will research the voter’s participation in the election before accepting or rejecting the provisional ballot. 

Attempting to vote more than once is a crime punishable by up to three years in prison, according to Elections Code section 18560. Voters who attempt to vote more than once in an election will be referred to the San Bernardino County District Attorney for investigation and potential prosecution.