Mayor Shirley Marquardt is running for reelection.
She's the first person to declare her candidacy for city office, according City Clerk Cat Hazen.
Candidates have until August 18 to file for the October election.
Beyond the Mayor's seat, the ballot will include three spots on the City Council and three on the school board.
The notice of general election previously indicated that only two school board seats would be on the ballot. The city has since added a third seat, because it's held by a board member who was appointed mid-term.
Unalaska's city election will be held October 4.