The new case is a 45-year-old Thai man from the southern province of Narathiwat, authorities said.
The number of new cases have been declining in the last two weeks with the exception of a cluster at an immigration detention centre in southern Thailand that has seen 60 new cases in that period, said Taweesin Wisanuyothin, spokesman for the government's Centre for COVID-19 Situation Administration.
Since Thailand's outbreak began in January, the country has seen a total of 2,988 coronavirus cases and 54 deaths. Taweesin said 2,747 patients have recovered, while 187 are still being treated in hospitals.