You obtain your non-immigrant visa before you enter Thailand from an embassy or a Thai consulate in your home country.
If you go to the website address www.thaiembassy.org/ you will find details on all Thailand embassies and consulates in your home country including how to apply & shows the visa fee. Most countries allow you to apply via the postal service but not all.
If you are already staying in Thailand & meet the criteria but do-not have the non-immigrant visa in your passport at key visa co ltd we do guaranteed trips to a Thai consulate to obtain a non-immigrant visa ready to start your retirement visa application.
There are two options of a non-immigrant visa which are category O or B the non-immigrant O is a tourist visa & offered in a single entry or a multiple entry form.
The non-immigrant B visa is classed as a business visa & is also offered in single or multiple entry form. My advice is if you are coming to Thailand for long stay & wish to apply for the retirement visa when you arrive it is more cost effective to obtain the single entry non-immigrant visa which will give you a stay of 90 days when you enter Thailand & will give you time to prepare your documents ready for the retirement visa application.
Please note- you must apply for the retirement visa approx 3 weeks before the finish date of your 90 day stamp if you let the visa expire you cannot apply for the retirement visa until you obtain another non-immigrant visa.
At key visa co we advise all our clients to prepare there application as early as they can when they enter Thailand .There is no benefit of applying towards the end of your non-immigrant visa because when the retirement visa is awarded the visa start date is from the day before you entered Thailand on your non-immigrant visa