What is the best visa option for retiring in Thailand if I plan to apply while in the country?

Graham Seal thanks bud

Dave Morris On the 90 day single entry non-O visa, YES. What you need to do is go to the immigration office that covers where you live in Thailand (for example if you are staying in Pattaya the immigration office is in Jomtien) and take your rental agreement or proof of where you are staying (I think they expect a minimum of 3 month contract) and get a 'residency certificate' then take that along with your passport, a phone with thai sim in your name (if you want the phone app) and some banks are now requesting a secondary ID from you home country such as your driving license to a bank in the same area (for Pattaya I would use the Kasikorn bank on beach road in Jomptien as they are close to the immigration office and used by a lot of expats so know how to deal with it. Once the bank account is open you need to transfer the 800,000 Baht into it, I'm with HSBC so I just got the SWIFT code from Kasikorn and used that for a direct transfer and use the same method each year for my expenses. You have to allow the money to 'season' for 2 months before you can apply for the extension of stay and it has to be before the 90 day entry visa expires which is why you have to open the account quickly and get the money transfered all within the first month. It might sound a bit difficult but after the first dozen or so times of doing the visa/extension re-newal it become very easy.

Dave Morris yes I did

Dave Morris no you do not if you apply in your home country. You show funds in your home account. To get the non o IN THAILAND you need a thai bank account

Dave Morris not if you apply for the non o outside of Thailand .