Nine new coronavirus infections were reported on Wednesday, all from overseas -- an American family and five Thai returnees.
The Centre for Covid-19 Situation Administration said eight new patients took the total to 3,425, most of whom have already been treated and discharged.
The death toll remained unchanged since June 2, at 58.
A Thai man, 34, and a Thai woman, 36, arrived from the United States last Thursday. They were tested on Monday while in quarantine in Chon Buri, and the resuts were positive, although they were asymptomatic.
Four members of an American family proved positive in their second tests on Monday during quarantine in Samut Prakan. They arrived in Thailand on Aug 19. They were a man aged 48, a woman aged 49, a boy aged 15 and girl aged 13 years.
A 27-year-old Thai student tested positive on Thursday after arriving from Australia on Aug 24. He was in quarantine in Chon Buri and exhibited no symptoms.
A Thai woman, 29, who arrived from Japan on Friday was found infected with the virus on Monday. She was also asymptomatic, the CCSA said
In addition, Foreign Ministry spokesman Cherdkiat Atthakor said Mud Manin, a Thai staffer at the labour office in Riyadh, Saudi Arabia, returned to Thailand on a flight to Don Mueang airport on Wednesday, and was sent to Rajavithi Hospital for treatment of Covid-19.
This case is not yet included in the CCSA tally.