You can apply for Single entry tourist visa(60days) at then extend your stay for 30days. If you want to stay longer you can change type of visa such as education visa.

From my experience, my husband didn't apply for police clearance certificate.

To know more about marry in thailand pls read here

And for Thai immigration you can check the link from previous post.

No more STV

-Apply for 60days tourist visa, you can extend it 30days (or you can change type of visa later (non o married)​after get married certificate)

-Then quarantine 15days 14nights

-Go to Australia embassy in bkk or phuket for Statutory Declaration and certified passport copy. I am not sure that you have to make appointment or not pls ask

Both doc. you need it for register married certificate.

- Translate Statutory Declaration, Passport copy

- Get attested translation by thai consular (it will takes around 3-5days)

- Then you can apply for married certificate.

After that you can Change type of visa to non-o married before visa expired 15 days.

/06-edit_NON-O.pdf&ved=2ahUKEwjhtpDSm_PxAhWCxTgGHeSfCFcQFjABegQIIxAC&usg=AOvVaw2Is0RBINFgxskg-xc7NFSu