Bangkok Governor Sukhumphand Paribatra tendered his resignation Wednesday to pave the way for a gubernatorial election within the next two months.
Sukhumphand, a leading figure of the Democrat opposition party, resigned a day before his term was due to expire to avoid being acting governor during the campaign for the gubernatorial poll.
The election must be held within 60 days of Sukhumphand's resignation, and the Election Commission was expected to choose March 3 as its date.
By resigning, he has 15 more days to campaign for re-election because if there were an acting governor, the election would have to be held within 45 days.
Sukhumphand would contest the election for the Democrats. The country's oldest political party leads the opposition against the ruling Pheu Thai Party, which has yet to announce its candidate.
Earlier Wednesday, Sukhumphand went to the Department of Special Investigation to hear charges that he breached regulations by extending a contract for the city's Skytrain mass transit system for another 13 years without receiving permission from the Interior Ministry.
Bangkok's traffic was expected to be a key issue in the campaign.