Hello

Just wondering I have been entering Thailand for many years using my UK passport but I am a dual citizen and also have a new Australian passport. Can I get a single entry o visa (family) on my Australian passport from Uk and enter with that instead of using my Uk passport.I have a 6 year old son and have all documents. Just curious as I will be going back to Aussie more often than Uk. Thanks for all replies

Should be fine doing it that way.  Just make sure you don't get confused and give them the wrong passport at some point and screw up your visa/extension.

But the fact that you will be going to Australia more than the UK doesn't really have any factor at all in this equation.  You choose to enter Thailand with one passport and must exit Thailand with that passport, what you do other than that is irrelevant about entering or leaving other countries with whichever passport.

Thanks for your reply. I have had yearly extensions based on being father of child with Uk passport. Will it matter to immigration if I use Aussie passport for those extensions now. My uk yearly extension has expired. And also getting single entry o visa obtainable from Uk with Aussie passport. I will try and contact London consulate and ask them. Thanks

2 hours ago, Stanvac said:

Thanks for your reply. I have had yearly extensions based on being father of child with Uk passport. Will it matter to immigration if I use Aussie passport for those extensions now. My uk yearly extension has expired. And also getting single entry o visa obtainable from Uk with Aussie passport. I will try and contact London consulate and ask them. Thanks

No need to contact the embassy, you just need to apply for a non-O visit Thai family e-visa.  There is no reason why you cannot apply using your Australian passport.  You will need to demonstrate legal presence/residence in the UK at the time of application.

8 hours ago, Stanvac said:

Thanks for your reply. I have had yearly extensions based on being father of child with Uk passport. Will it matter to immigration if I use Aussie passport for those extensions now. My uk yearly extension has expired. And also getting single entry o visa obtainable from Uk with Aussie passport. I will try and contact London consulate and ask them. Thanks

 

As long as you start over with a new Non-O visa obtained outside of Thailand, as per your plan, there's no problem "switching" nationalities.