The appropriate visa created to allow U.S. citizens to bring their Thai girlfriends to America, not to tour the country but to get married is on a K1 visa. It is a single entry visa which is only valid for one visit to the U.S. and can only last for 90 days. Upon arrival in the U.S., you have 90 days to marry her or else it would be considered as a visa violation on her part. After the marriage, she must then travel back to Thailand and apply for a Settlement visa for her to stay with you for long term in the US.
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