I see there are 2 ways to retire in Thailand.

1/ Get a non-immigrant type OA visa from your home country.

2/ Within Thailand, convert travel visa to non-immigrant type O (for retirement).

Since 1/ requires medical and police checks and 2/ does not I am leaning to method 2/. Can I just apply for the type O in my home country? I'm guessing not since I haven't seen it mentioned anywhere, unless the reason is for eg marriage.

Also, just curious, regarding the type O, does it get converted at any time to OA , like when I go for yearly extensions? Or type OA's are always OA and type O stays O.

Yes, you can apply for non-imm 'O' visa when over 50 in your country. You have to check with the local Thai embassy or consulate for the requirements that vary from a country to another.

Extension of stay for retirement can be obtained with any type on non-imm visa, not just O-A.

Extension of stay and visa are very different things, even if people often thinks they are the same.

Unless there is a honorary Thai consulate in your home country you will probably not be a able to get a single entry non-o for being 50 or over. The embassy and official consulates will not issue them because they only do the non-oa visa,

Looking at a topic you started you appear to be in Canada. There are 3 honorary consulates (Vancouver is not one) where you can get a non-o visa. Contact info here: http://www.thaiembassy.ca/en/visiting-thailand/visas/obtaining-visa-canada

Thanks for the replies. Contacted (honorary) consulate in Toronto and they do not issue non-immigrant type O's for retirement. I will likely get a single entry travel visa and flip it to a non O /retirement when I get there.

Unless there is a honorary Thai consulate in your home country you will probably not be a able to get a single entry non-o for being 50 or over. The embassy and official consulates will not issue them because they only do the non-oa visa,

Looking at a topic you started you appear to be in Canada. There are 3 honorary consulates (Vancouver is not one) where you can get a non-o visa. Contact info here: http://www.thaiembassy.ca/en/visiting-thailand/visas/obtaining-visa-canada

Ubonjoe is Canada different to AU. I was advised that at Melbourne I can only get a non imm O and if wanted an O-A , I would have to go to Sydney or Canberra. Sort of surprising as Melbourne is a city of 4 million people.

Were you asking for a single or multiple entry non-o. Perhaps they have changed their rules because of a directive from the embassy. It has not been that long since we had reports for them doing non-o visas for being 50 for or over.