The Election Commission on Monday approved the result of the May 22 local government elections in Pattaya, underlining the political hold of the Kunplome family on the resort city.
The EC ruled that the polls were transparent and fair, but said the results were still open to investigation if complaints were filed.
The election saw Poramase Ngamphiches of the Love Pattaya group being elected city governor, with about 14,000 votes - about 2,000 votes more than his closest rival, Sinchai Watthasartsathorn of the Pattaya Ruam Chai group.
Mr Poramase ran for the job after outgoing governor Sonthaya Kunplome decided not to run. He shifted his attention to preparing his Palang Chon faction, now under the Palang Pracharath Party umbrella, for the general election.
Mr Sonthaya endorsed Mr Poramase as his successor.