I have heard from many people that claim to have opened a bank account with no more than a passport. I have heard the passport and a letter from the embassy. I got denied at Siam Commercial Bank in the mall with a current non O visa, a letter of employment (not in thailand), Thai drivers license, a letter from the embassy, and my wife standing there with her account book from that bank. I have come to the conclusion that it is only the branch you go to as to weather they will give you an account