Officials said the river started to overflow at 1am and residents of Tambon Kuan Pring, Tambon Na Talung, Tambon Nong Trud and Tambon Bang Rak were evacuated to tents prepared by their tambon administrations.
Following days of rains, upstream waters from Nakhon Si Thammarat and Phatthalung have been flowing into the Trang River to go out to the sea.
The Trang Disaster Prevention and Mitigation Office reported that, so far, about 30,000 people in seven districts of Trang have been affected by flooding.