Travelers should declare all items being brought from abroad that will remain in the United States. This includes gifts and duty-free purchases. Goods purchased in a duty-free shop are not automatically free of duty upon your return to the United States.
A passport and a boarding pass are required when you declare on the form. If you enter Thailand via land/sea, you will need to have cash of or equivalent to 20,000 Baht per person or 40,000 Baht per family.
You won't want to carry too much cash with you in Thailand, so using a card is ideal. However, your regular bank card may come with high foreign transaction fees. Avoid this by getting a dedicated travel money card from a service like Wise or Revolut.
This is frowned upon and in fact illegal (though of course the law is seldom enforced - unless drunk and bad-mouthed too). the max fine is actually 500baht! For women, when walking around - do wear a bra. Thais frowns upon western women they see bra-less.
Checked Bags: YesSolid food items (not liquids or gels) can be transported in either your carry-on or checked baggage. TSA officers may instruct travelers to separate items from carry-on bags such as foods, powders, and any materials that can clutter bags and obstruct clear images on the X-ray machine.