The ban on incoming flights came into effect on April 4 morning and will last until the end of April 6, according to the Civil Aviation Authority of Thailand.
Anyone arriving on a flight that took off before the order came into effect will need to be quarantined for 14 days upon arrival in Thailand, the order said.
It came just hours after a commotion at Bangkok's Suvarnabhumi airport when more than 100 Thai nationals arrived on different flights on April 3.
Thailand, which has reported 1,978 COVID-19 cases and 19 deaths as of April 3, wants to avoid importing more cases.
Since March 1, there has been a rising number of people who were infected abroad before returning home. The authorities have put nearly 2,000 people who came into contact with them in quarantine.
The ban on incoming air travel came a day after the Thai government asked citizens abroad to delay returning home until after April 15 in a bid to stop imported cases.
