Does my daughter need to transfer her visa stamps to a new passport before exiting Thailand?

Another thing is, do you want your daughter to have a chance to live in Thailand long-term in the future?

If yes, you have to cancel her extension officially before she leaves Thailand. To do it, the stamps have to be transferred to a new passport.

(I cannot come up with a reason for her extension that is not required to be cancelled, such as "being over 50" <- no reason to cancel)

If an old and "supposed-to-be-expired" extension is remaining, it will cause an issue when the holder wants to apply for a different extension in the future, even after years have passed.

Same for you, if you are on an extension currently, and there is even a slim chance you will be back to Thailand as not-a-tourist, you should cancel your extension officially before you leave.

If none of you will ever be back to Thailand other than a tourist for short holidays, you can just leave.

Transferring over the stamps is a waste of pages in the new passport. I’ve never heard of anyone being prohibited from leaving Thailand over an issue like this.

It would be a different story if you were coming back but I would just not worry about it since you aren’t.

If you leav permanently you not need that visa anymore.. And if you get a new passport before you ask passport office to keep the valid pages intact.

If you want to transfere the stamp and extent it for one more year you need RE entry permit as well

So she has an extension, not a visa. It would be prudent to move the stamps to the new passport prior to leaving the country.

IF your daughter is in Thailand during the first 90 days she got on entry using this Non Immigrant O visa or by conversion at immigration, the visa is stamped used and can not be transferred into a new passport.

She can leave using both passports.

Does she actually have a VISA ?