The times when you got a 16 to 18% interest rate on a three month time deposit are over since the Asian Crisis in 1997. But still, having a bank account in Thailand is the safest way to keep your money.
The banking system has greatly improved over the last years. You will always get an ATM Card for your account, some of the bigger banks even offer international credit (debit) cards instead of ATM Cards to their customers. (Bangkok Bank, Siam Commercial…) In the towns and at the tourist centers you will find those ATM machines on every corner and they usually display Thai & English.
Opening an Bank Account in Thailand is not always as easy as it could be. Bank clerks will usually first ask your passport and a workpermit to let you open an account.
If you don`t have a workpermit, you will need at least another ID such as your driver´s licence. In your passport you should have a Non Immigrant Visa or a Tourist Visa and you might need a Residence Certificate as proof of address.
If it doesn`t work in the first bank, try another one and another until you find one that will do it for you.
Try another Bank
I recently managed to open an account with Bangkok Bank in Krabi, providing my passport with a tourist visa, a residence certificate from the immigration office and my German driver´s licence as a second ID. The branch of the Bangkok Bank was the third bank I tried.
A residence certificate you can get at the local immigration office for free, when your landlord has registered you at your rented house address with the Immigration. He has to do that within 24 hours after you moved in his house or flat.
Foreigners can also open a time deposit account in foreign currencies such as US Dollar, Pound Sterling, Australian Dollar, Swiss Franc, Hong Kong Dollar, Euro and Singapore Dollar. There are however some restrictions on that, please aks your bank in Thailand for details.
Please be aware that there is no need to open a bank account in Thailand in the name of your thai girl friend or another thai friend, just because it might be easier. A lot of foreigners lost all their money that way.