|Can a non-U.S. citizen open a 529 account?|
Yes, with a few limitations. Section 529 plan account applications generally ask for the Social Security number of the account owner and the beneficiary. If you will be the account owner and you don't have a Social Security number, check with the administrator of the 529 plan before you send any money to see how you'll be handled. Some 529 plans allow resident aliens to be the account owner, but normally these plans still require a Social Security number.
Another issue can be state residency. Some 529 plans require the account owner to be a resident of their particular state (for a certain time period) before an account can be opened. Alternatively, some plans require that either the owner or the beneficiary be a resident. So if the beneficiary is a resident, you may still be able to open an account even if you're not a U.S. citizen or resident.
You may expect the beneficiary to attend a foreign college or university. Some foreign colleges and universities are recognized by the U.S. Department of Education as "eligible educational institutions"--a key factor in the income tax treatment of withdrawals from the 529 plan. You should still check the requirements of the 529 plan you are considering to make sure a particular foreign college is an eligible institution.