The government reported 22 new cases of the novel coronavirus on Monday, raising the total to 3,545. The death toll was unchanged at 59.
Sixteen of the new cases were from South Sudan, four from India, one from Pakistan and one from the Philippines.
The Centre for Covid Situation Administration (CCSA) said all 16 new cases arriving from South Sudan were Thai soldiers returning from a UN peacekeeping operation in the African country.
They returned to Thailand on a charter flight on Tuesday and were quarantined in Chon Buri province. Their test results on Saturday were positive, although all were asymptomatic. They were transferred to Phramongkutklao Hospital after the tests.
A 24-year-old Thai soldier studying in the Philippines tested positive on Saturday. He had arrived in Thailand on Wednesday and was quarantined in Chon Buri. He was asymptomatic, and sent to Laem Chabang Hospital after the test.
A Thai male student from Pakistan, 13, tested positive in his second test on Saturday despite being asymptomatic. He arrived in Thailand on Sept 13 on the same flight as two other passengers who were found to be infected.
The four new cases arriving from India were Indian nationals. Three of them arrived on Wednesday and tested positive on Saturday -- a mother, 35, her seven-year-old daughter, and a businessman, 38. The fourth case was a 30-year-old man who arrived on Friday and tested positive the same day.
None of the Indian cases showed signs of the disease.
Aside from the latest cases, the CCSA agreed in a meeting to extend the emergency decree for another month to Oct 31.