I am over 50, travel on an Oz passport and would like to stay in Thailand next year from 15 July - 30 October 2023 ( then spend 2-3 months in Europe ) and then come back to Thailand from 10 January to 30 May 2024.

I assume that applying for a non-immigrant visa type O-A valid for one year at the OZ consulate in Sydney is the easiest way to stay for the periods mentioned above.

Question 1 : Does such a visa allow you to leave Thailand ( in this case for thereabout 2-3 months) and come back in ? Do you need to apply for some kind of re-entry visa when you leave ?

Question 2a: Could I apply again for the same type of visa (non-immigrant O-A valid for 1 year) in September 2024 ?

Question 2b: Given that I have dual citizenship ( OZ & French) and will apply for this visa to the Thai embassy in Paris , should I use my OZ passport or would it be better to use my French passport for this visa ?

I don’t want to get into trouble with the Thai immigration for using two passports.