Question on expiring passports and extension of stay.

I have an OA visa and I am on an Extension of Stay to October 2025 (multi-entry). I do the extension in early September each year.

My (Australian) passport will expire in January 2026.

I have read various posts about this and it seems to me that the simplest approach is to get a new passport before attempting the extension.

I think I can renew the passport in Thailand, but this seems quite a lengthy process.

As an alternative, I have no problem with renewing my passport in Australia mid-year prior to doing the extension in Thailand in September. But that will mean that I leave Thailand on the old passport, and return with the new.

As I understand it, I simply show both passports on return and get the existing extension moved to the new passport once I have arrived.

What is unclear to me is

(a) I have an existing multi-entry stamp in my old passport. Is this still valid (and thus allowing re-entry)?

(b) Once arrived back in Thailand, do I need to immediately "transfer the stamps", or can I just wait until I do the extension, (showing both passports + associated paperwork/insurance/funds etc), as the new extension will go straight into the new passport.

Looking for advice on flaws in my logic/understanding.

Thanks all.

My passport expires 4th Nov 22

Waiting for New one to arrive.

My 90 day is duevon24rth Sept

If My new passport has not arrived in time what can I do please

My 90 da

Greetings,

My American passport 13, March 2018 and my non-O visa (retirement) needs renewal by 13, March 2018.

Which should I renew first and how soon should I get going on this?

Thank you.