My experience is with the Chaengwattana Immigration office in Bangkok to get a 1 year extension. I would obtain bank documents before going. They are valid for 7 days. I updated my bank book downstairs using the machine that is available even when the bank a not open. I would arrive around 8am. The office opens at 8:30am. I usually got my queue number 15 minutes later. I typically got my extension completed within 2 hours. I didn’t use and agent or make an appointment.
If you are also getting a re-entry permit then you are going to have to get in line again.
Avoid going the day after immigration has shut down for holidays. Note there are a lot of holidays in April.
Just get there early when the office opens at 8:30am.
IF you do plan to bring a sizable amount of cash to deposit in Thailand then don’t forget to bring pristine unblemished notes with you. Prearranged this with your bank back home.
He was asking about depositing cash. My understanding is that you have to show that the monthly deposits originated from overseas. You can do that with electronic transfers but I don’t know how you could do that with cash deposits. You are correct though that once the money is deposited then you can spend it down to zero until the next month.
It is just a regular bank account in your name. I had only one bank account with the 800k, a 400k buffer, and then added my monthly operating funds on top of that. As long as you maintain the proper minimum balances to meet the visa and extension of stay requirements then you can deposit money any way you want to.
If you switch to the 65,000/month method then I think you have to show that the money came from outside Thailand and for that you probably can’t make cash deposits.
I had an OA visa for 6 years. I have a Pacific Cross insurance policy that satisfied the OA health insurance requirement. Each year, when I renewed my policy, they sent me an insurance certificate document and registered the policy in the Immigration database. When I applied for the pensioner LTR visa I submitted the same insurance certificate to satisfy the LTR insurance policy. There is also the option to show that you have $100,000 deposited in a bank account but I did not do this since I already have the insurance.