The people of Bangkok and Pattaya will to vote for new city chiefs and councillors on May 22.
The Election Commission announced on Monday it had decided on May 22 for elections in the two cities, and the date would be officially declared on March 25.
The elections would be for city chiefs and councillors.
In Bangkok, former transport minister Chadchart Sittipunt has a comfortable lead over other prospective candidates for city governor, according to the monthly opinion poll by the National Institute of Development Administration.
Of the others, in the latest survey released on March 6 Wiroj Lakkhanaadisorn of the Move Forward Party had a slight edge over Democrat Party candidate Suchatvee Suwansawat for the first time.
Sakoltee Phattiyakul has joined the race after he stepped down as Bangkok deputy governor last Monday.
The current, appointed, governor, Pol Gen Aswin Kwanmuang, remains tight-lipped about his future. The governor’s supporters hope he will compete in the poll.
Former street protest leader Suthep Thaugsuban last week declared his support for Mr Sakoltee, a former member of the now defunct People’s Democratic Reform Committee and son of Gen Winai Phattiyakul, who was secretary-general of the former Council of National Security that ruled after the 2006 coup.
Gen Winai is a friend of Deputy Prime Minister Gen Prawit Wongsuwon.
In Pattaya, Mayor Sonthaya Kunplome is keeping people guessing about his plans, saying only he that is ready for another run.
Culture Minister Itthiphol Kunplome said on Friday he expected his elder brother would stand for another term as he had plans to make Pattaya once again a holiday city, serving the Eastern Economic Corridor.
The Progressive Movement was expected to announce its candidate to challenge Mr Sonthaya later on Monday.