I have searched through all previous posts looking for this but unable to locate a similar situation. Most situations deal with marriage, I am single.

I am currently working in Thailand on a Non-Immigrant B visa, recently renewed for one year. I have a valid work permit. I will be turning 50 soon and plan to quit work and retire and would like to change my visa to a Non-Immigrant O. I have had the 800K in the bank for over 4 months.

Do I have to leave the country to do this? Or can it be done in the local immigration office?

Thank you in advance.

Apply for a 12 month extension of stay at Immigration in Thailand.

Reason. Retirement.

Update your bankbook and have a letter from the bank confirming your saldo. Do it the day before you go to immigration.

A map to you residence might be asked for together with some proof such as rent receipt/lease. The fee for extension of stay is 1,900 baht. If you plan to travel abroad during the period of the extension remember you will need to obtain a re-entry permit from immigration to keep your permission to stay alive. Fee 1,000 baht single entry; 3,800 baht multi entry.

This change of extension must be done at the same time that you end your work.

This change of extension must be done at the same time that you end your work.

My passport has a multiple entry stamp in it now. When I retire and change the extension can I keep the multiple entry stamp or do I have to get a new one?

A re-entry permit is only valid for the duration of your current permission to stay, which ends when you get a new permission to stay. So you have to buy a new (multiple)re-entry permit when you change your reason of stay, and every year when you get a new extension of stay.