According to immigration parent visa extension is ok with letter from school, proof of relations and 500,000 baht in bank for a month  before application (first one). However, I do not see any information whether the previous incomprehensible rule of one child - one visa extension is still observed, effectively making all one child families to have a single parent in Thailand. Is this still the case, or now both parents can get extension with only one child in school?

It is still only one parent per child that can get the one year extension of stay (it is not a visa).

Thanks. Thats what I was worried about. Can non-Imm. O be extended for a shorter period of time than a year?

40 minutes ago, johnth said:

Thanks. Thats what I was worried about. Can non-Imm. O be extended for a shorter period of time than a year?

The 90 day entry from a non-o visa can only be extended for one year.

If the child's extension of stay for attending school ends in less than a year the extension for the parent will only be issued to that day.

But my wife already has guardian visa extension linked to the education visa. Would they grant another non-Imm O extension given she already has one?

21 minutes ago, johnth said:

Would they grant another non-Imm O extension given she already has one?

They would issue her another extension when it it expires. But they would not issue you one if hers was still valid.

Her is valid at the moment, as they run out in March (her and kid same time)

 

Mind you, the Immigration website does not mention anything about this limitation as long as you fulfil all other requirements