The Thai Civil Aviation Authority of Thailand, or CAAT announced this evening that they have extended a ban on international inbound travel to Thailand until at least the end of June.
This has very limited exceptions, such as repatriation of Thai nationals or supply and cargo. Foreigners, even those with work permits, family or elite visas, even willing to do state quarantines, will remain banned from entry.
Exceptions, including repatriated Thai nationals, will still be required to do a fourteen day mandatory state quarantine and show they are negative for Covid-19.
This means the earliest a foreigner could possibly enter the country would be July, if the order is not extended again. Even if not extended it is likely the order would require mandatory quarantines on arrival.
Here is the order in Thai