Trang province was on Friday night hit by heavy rains for more than six hours, causing flooding in several areas in the town and its outskirts.
Several families living in low-lying areas were forced to evacuate overnight as flood water rose quickly.
Local authorities said several communities in the town were submerged after it rained for several hours, forcing people to move their belongings to higher grounds and evacuate after water level rising to almost a metre high.
Town residents said the town was submerged by surface runoff from surrounding hills and rising water that could not be drained due to clogged drains from garbages.
The Southern Meteorological Centre warned of continual rainfalls as the southeasterly monsoon is still blowing into the Andaman Sea in the South and the Gulf of Thailand.
The monsoon wind will bring about more rains in several provinces which include Phetburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, and Songkhla.