You need to have stayed for months at a permanent adress on a long lease or owner, show a monthly large deposit to the account, which are easy traceable.
or in short be reagarded as a thru resident and not a tourist.
Banks in Thailand are like everywhere in the world, interested in having good stable custormers, that have a permanent address, a steady easy traceable income, and use the account all year round.
That is why the banks are reluctant to give accounts to people on short time ( read: tourist ) visas, and who only spend part of the year in Thailand.
Don’t expect to get a residence certificat, until you have stayed at a permanent adress in at least 3 month, since that is what the residence certificat should confirm.
Furthermore the added attention on whitewashing of money, is an added burden on the banks, so reluctant depositing large amounts isn’t a guaranteed way to open an account.
The value of a resident certificat, had gone down, since Immigration Officers are giving them to people that are not on a longterm visa, or have stayed severel months at 1 adress in Thailand, so even if it is a formal requirement, the bank make up their own assesment of the stability of the want-to-be customer.
Passportholders from 93 countrys are getting 60 day visa exempt when arriving in Thailand, with the option to extend 30 days at a Immigration office ( 1900 Baht )