đŽ IMPORTANT UPDATE: I have just been informed by my source in the Consular Department at the Ministry of Foreign Affairs that Thailand Pass holders using Test & Go can now change to an earlier arrival date. You just need to write to them with the details. Email tfcovid19@mfa.go.th or if you're going to Phuket phuket.thailandpass@gmail.com.
I've been told that the Ministry of Foreign Affairs really hopes that everyone who successfully applied for Test & Go will be allowed to enter no matter when that is. They, nor the TAT, want a cut off date. The situation is still being assessed. We might hear something on Sunday. Hopefully it will be good news for everyone.
I just want to finish this post by say there is currently NO cut off date to arrive in Thailand despite what you may have read in the media. This date is still being discussed. The MFA tell me there may not even be a date. People arriving in the next week are safe for sure. The CCSA are still assessing whether to allow Test & Go people to arrive after 15th January without having to do quarantine. More news soon.
Good luck!