I do not recommend the 1-year Non-Imm-O/A Longstay visa if you want to permanently retire in Thailand. I recommend the 90-days Non-Imm-O Retirement Visa instead.
These are the requirements for the application to a Non-Imm-O Retirement Visa inside the USA only
For the application to the “1-year Extended Stay Permit based on Retirement” inside Thailand, the requirements are slightly different (the financial proof can only be made with the 800,000 THB deposit in your Thai bank account, at least in the first year)
Non-Immigrant Type “O” Retirement
Validity of visa: 90 days (single entry)
Fee: 80 USD
Purpose of Visit:
This type of visa is for pensioners aged 50 years or above who wishes to stay in Thailand for a period of not exceeding 90 days without the intention of working. Holders of this type of visa are allowed to stay in Thailand for 90 days. Employment of any kind is strictly prohibited.
Eligibility:
1. Applicant must be aged 50 years and over (on the day of submitting application)
2. Applicant not prohibited from entering the Kingdom as provided by the Immigration Act B.E. 2522 (1979)
3. Having the nationality of or residence in the country where applicant’s application is submitted
If the applicant does not have a valid visa or re-entry permit, the applicant must request a visa, at least 15 working days before the intended date of travel, by filling in the information and uploading all required documents online in the E-Visa System of the embassy Washington DC (Please note that the visa application fee is non-refundable)
For instructions, please check the E-Visa online manual
Required documents to upload in the system (Large and clear JPEG or PDF format):
***Passport Biodata Page or Travel Document (Must be valid within 6 months from travel date)
***Photograph of the applicant, taken within the past six months
***Document indicating current location (driving license, bank statement, or proof of stay)
***Recent bank statement showing the applicant's name and ending balance of no less than $30,000
or
proof of monthly income of not less than $2,500/month) along with the current bank statement showing incoming income
You can also apply for a 90-days Non-Imm-O Retirement Visa inside Thailand as well, after entering on a tourist visa or visa-exempt. However the requirements differ a lot, and you will need a Thai bank account as soon as possible right after entry, which is almost impossible for now.
For the application to the initial 90-days visa in the E-visa system of the Thai Embassy, you either qualify with original proofs of your income or proof of money in your home bank account of a minimum of equivalent to 800,000 THB
However, for the application to the 1-year extension of stay, you need the minimum of 800,000 THB in a Thai bank account in your sole name, at least in the first year of the Extension of Stay.
Because the U.S. Embassy in Bangkok will not issue a legalized "income affidavit", so you can only use the "800,000 THB deposit method”.
Only after having collected 12 consecutive months of transfers from abroad to your Thai bank account, of a minimum of 65,000 THB, month for month, you can switch to the financial proof by the 65,000 THB income method
The steps to a 1-year stay permit based on retirement in Thailand are:
***You ENTER on a 90-days Non-Imm-O retirement VISA.
***You will get stamped in for a 90-days STAY PERMIT.
***you need to open a Thai bank account in your name as soon as possible and transfer the required 800,000 THB minimum onto it
***Then before these 90 days expire, you need to apply for the EXTENSION of the STAY PERMIT "based on retirement/over 50 years old".
***This extension of the stay permit is NOT a "visa", despite people calling it "retirement visa". It is an “extension of a temporary stay permit based on retirement”
You should visit Immigration right after you enter and ask them for their handout regarding the application to the 1-year Extension of Stay based on Retirement, as some Immigrations differ a little bit from others