What documents do my kids need for border bouncing in Thailand, and are they exempt from visa requirements?

If there kids the really don’t need any visa they will not get fined for overstaying

Only one exemption they have - kids will not be fined for overstay, but for entry they should match rules for passport country.

Children have the same requirements as adults, there's nothing special about that.

If you and/or your children are visa exempt for Thailand depends on what passport they hold. Different entry points generally have different requirements. Passport, possibly 20,000 baht in cash, 40,000 baht per family, proof of lodging in Thailand, proof of onward travel within 60 days are all things they can ask for.