Originally Posted by
bankops
Thai Ministry of Foreign Affairs:
That's not what is published in TIMATIC.
Assuming a US citizen, departing China headed to Thailand for tourist reasons the passport need only be valid for the intended duration of the stay:
National USA (US)
Embarkation China (People's Rep.) (CN)
Destination Thailand (TH)
Thailand (TH)
Passport required.
- Nationals of USA can enter on passports or passport
replacing documents valid for the period of intended stay.
Visa required, except for A touristic stay of max. 30 days:
Additional Information:
- Visitors who are visa exempt are required to hold documents
for their next destination.
- Visitors over 12 years of age are required to hold
sufficient funds to cover their stay (at least THB 10,000.-
per person or THB 20,000.- per family).
For details, click here
- For those who do not require a visaFor details, click here
Warning:
- Visitors who are visa exempt but do not hold return/onward
tickets could be refused entry.
Sounds like the OP was unduly denied boarding.