Six out of 32 Thais who recently returned from Japan on a repatriation flight were sent to hospital after failing a health screening test at Suvarnabhumi airport on Wednesday.
The group was stranded at Haneda airport in Tokyo after the Civil Aviation Authority of Thailand (CAAT) extended the ban on all commercial flights into the country until April 18.
The Thai embassy in Tokyo chartered a flight for them to return home after some passengers pleaded on social media for help.
But health officials at Suvarnabhumi airport recorded high temperatures in six of the passengers and sent them to hospital.
The rest of the passengers were taken to a hotel in Bangkok for a mandatory 14-day quarantine.
The government on Tuesday said it will not allow more than 200 people to enter Thailand per day.
The Centre for Covid-19 Situation Administration said more than 100 Thais are stranded in airports in several countries, with at least 60 in South Korea, 60 in the Netherlands and one each in the United Kingdom and Qatar.
CAAT is still allowing special repatriation flights to enter the country during the ban.
Natcha Lapaaneknan, a passenger who was stranded in Tokyo, said on Facebook that she had booked a flight to Thailand from the US on April 2, but the plane landed in Tokyo on April 3 without prior notice.
They later learned that Thailand had cancelled all incoming flights.
The flight was then rescheduled to depart on Tuesday but was cancelled again after Thailand extended a restriction on incoming flights until April 18.
Ms Natcha did not have a visa to enter Japan and was forced to sleep on seats at Haneda airport.
