What is the process for obtaining a tourist visa for a Thai spouse to visit the USA?

never say never

I have understood that if you are an American citizen residing in the US it’s easy to get a fiance visa to bring your fiance to America. Then you have 6 months to get married in the US. Once that happens, the new spouse can get a change of status and green card pretty quickly. Has anyone tried this?

Well, in my case (many years ago) we married in Thailand and then initiated the process to bring my Thai wife to the USA. It took some three or four months before she was approved to travel, and a faculty colleague who had previously been a US Foreign Service Officer (US Department of State) observed that (1) that was unusually fast, and (2) most of the delay is just "documents walking from office to office" (and two years later we got her "green card," which was really pink and, if memory serves, identifies her as an "Alien" (as in "Daddy, Daddy, you married an alien" -- a true joke heard from someone else). That said, I strongly recommend the route we took, as it provides you more options going forward -- and I was also allowed to "financially guarantee" my wife, even though I was a graduate student with practically zero financial resources... Good luck!

My wife and I got married in my home state then had to send it to Washington DC to the state department for an apostle, or whatever it’s called. Then we registered in Thailand when we moved here. We now have a son born here in Thailand and need to get him registered with the US. I’m worried about problems when we visit the US but not yet. Interesting though, I didn’t know it was so hard to get a tourist visa, I met her in the States while she was a student.

From what I understand, it's not that difficult as long as your marriage was registered with the US govt for at least 5 years.

Assuming people who want a holiday in usa want to live in usa. .

Yes. My wife and I were in the exact same situation last year. She had been denied a tourist visa before we were married or even engaged in Bangkok. I was still living and working in the US.

After I moved here permanently and we got married we wanted her to be able to travel back with me but didn't want to apply for the cr1 and have to stay there. So we thought we would give the tourist visa a try again in Chiang Mai. On the application I just picked a random field that allowed me to type what i wanted and explained the situation. Not sure if it was that or if chaing mai is a little more lenient but she was granted a 10 year tourist visa, which was all we needed. So it can be done.

If you search for B2 visa in the group, you can probably find some previous posts. Just know that it's very difficult for a Thai to get a tourist visa to the US.

Being married won't help your wife's case at all, and may even be an impediment. She will need to convince them that she's not just going to the US to apply for a change of status once there.