Ex wife intends to change kids�f surnames

Hello,

My children are Australian citizens.
My ex wife intends to change their surnames whilst overseas via marriage in Japan with her current partner. Will this affect the validity of their citizenships or their Australian birth certificates?

Shouldn't

They'll be asked to choose a nationality when they are 18 (maybe the age has changed) but even then it doesn't really matter.

So their full names will remain intact in Australia?
Thank you for your response by the way.

This is more of an Australia question than a Japan one really. They are Australian citizens and the only thing in question really is what (if anything) they are required to do according to Australian law upon changing their names abroad. I recommend asking the relevant Australian authorities.

You�fd need to check on both Japanese and Australian sides.

Just because your ex-wife gets re-married, it does not mean the children�fs family name would change automatically - as far as I know, the new husband would have to go through some adoption procedure to be able to get them into his �gkoseki�h (family register) and for them to have his family name. I hope your ex has figured out the implications of getting the kids to change their family name and have talked this through with them (I don�ft know how old they are).

And then comes the question of the Australian authorities - if she changes it officially in Japan, i don�ft even know if there is a way for them to change it officially on the Australian side, not to mention what happens to their nationality (which should remain intact, but in any case, there has to be a full paper trail of their birth, their name upon birth, the change, etc. as evidence).

It would be odd if surname decided citizenship. Never heard of it.

@AK, this is not true. Childrens names can easily be changed in Japan. The son of my wife also has my name but we didn't go through adoption or anything alike.
It may also be different depending on the nationality she's getting married to but a name change appears to be really easy.
The question here is if the name on the Australian passport / register can even be changed. We did the name change before registering our marriage in my country(european one) as a name change would have not been allowed by law afterwards.

To max,
There seems to be a few different patterns - whether the woman gets married into the new husband�fs �gkoseki�h and move the children in together, or the woman gets married but the children stay in hers, and things like that - and it is true, I�fm not exactly sure what happens if she had changed her family name to the first husband who was non-Japanese, then remarries�c sorry if I was completely mistaken.

@AK & @max, thank you both for your responses. Greatly appreciate it.