Pattaya City was partially flooded after more than an hour of heavy rain early Thursday morning.
Flooding was reported on a road parallel to a railway from Soi Khao Talo to Soi Khao Noi at 5am. It became impassable for motorcycles and passenger cars as water was between 10 and 70 centimetres deep. Many vehicles broke down there.
Local officials placed steel barricades to close the road.
Flooding was also reported on sections of major roads in Chon Buri, including Sukhumvit Road and the Bueng Bypass, disrupting travel towards Pattaya and Rayong.
There are flood-prone areas in Pattaya as many parts of the city are low-lying. However, flood drainage normally finishes quickly.
Pattaya Mayor Poramese Ngampichet wrote in a recent social media post that work is continuing to replace many old drainage pipes that are only 60cm in diameter.
Work has already been completed at more than half of the 20 chronic flooding spots that officials have identified, he said.