Yes. Thailand tourists can buy health insurance for the USA either before departing from Thailand or after arriving in the United States, provided they meet the plan's eligibility requirements. Thai citizens traveling on a B-2 tourist visa are not required to show proof of health insurance to enter the USA (Thailand is not part of the Visa Waiver Program, so a visa is required for entry). However, Thailand does not have a reciprocal healthcare agreement with the United States, and visitors are responsible for paying the full cost of any healthcare they receive.
Because medical care in the USA can be expensive, many travelers purchase visitor health insurance for Thailand tourists in USA through American Visitor Insurance to help protect themselves against unexpected medical expenses during their trip. Choosing a plan before you travel also ensures you have coverage in place from the day you arrive.