Honolulu elections officials say they plan to start mailing primary election ballots on Wednesday, about six days earlier than initially anticipated.

Ballots were expected to start dropping in voters’ mailboxes on July 26, which marks a deadline set by state law of 18 days before the election. But some Oahu voters could get their ballots as early as this week.

More than 478,000 mail ballots are set to go out to Oahu voters on Wednesday and Thursday. There are more than 561,000 registered voters on Oahu. But those deemed inactive — those whose addresses can’t be verified — won’t be receiving mailed ballots.

There’s a chance some voters will receive multiple ballots for people who previously lived at a certain address or registered but moved away, according to Honolulu Elections Administrator Rex Quidilla. In the past, people got ballots for their dead relatives. Much of that has to do with how often, or not, voter rolls are purged.

Oahu voters will have more locations to drop off their ballots. The city is adding three new drop boxes in Ewa Beach, East Honolulu and in Salt Lake. All 13 ballot drop boxes are set to open Thursday.

Voter service centers at Honolulu and Kapolei Hale are set to open Aug. 1. This year, the city is adding two additional voter service centers. The first will be open from Aug. 1 through Aug. 5 in Kaneohe. Then, another center will open in Wahiawa between Aug. 8 and Aug. 12.

Only the voter centers in Honolulu and Kapolei will be open on election day, Aug. 13. The centers are closed on Sundays.

Ballots either need to be received by elections officials or left in a drop box by 7 p.m. on Aug. 13. Voters at a voter center who are standing in line by that time will still be allowed to vote.

Elections officials are urging the public to mail their ballots as soon as possible. If in doubt, they said, use one of the drop boxes.