If you stay in Thailand as a retiree, you might have to transfer your pension every month to your ATM bank account to Thailand, to have access to your money at Thailand’s ATM machines.
This money transfers however, usually cost a lot of money for fees. In your home country as well as in Thailand, when it arrives.
Another way to get access to your money is a credit card. You leave your funds at the bank account at home and withdraw it in Thailand with your credit card at the ATM machines.
Thai ATM Service Charge now at 220 Baht
This way however, you have to face the fees of your credit card for use in foreign counties plus a “Service Charge” of 220 Baht for every transaction in Thailand with foreign credit cards.
To avoid at least some of this charges, I would reccomend to you a free online bank account that comes together with a free VISA Card in your home country. This accounts usually offer free money access at ATM machines worldwide, not only in Thailand.
I am using one of this accounts by myself, from a Bank in Germany and I believe a similar offer should be available in any civilized country in Europe and the US.
I can not get around the Thai Service Charge anymore but at least I will get back the fees of my home bank.