Can I apply for non o visa based on having a child (not married) in PP?

Used to always apply in Vientiane without trouble, can I do the same kn PP?

You might be able to get a single entry non-o visa but there have been no reports I can recall of anybody getting one there for being the parent of a Thai.

According to their website they will only issue a non 'O' if married to a Thai. No mention of being a parent. The website may be wrong/out of date.

http://www.thaiembassy.org/phnompenh/en/information/6067. It might be worth trying through a visa agent.

If you can't get a non 'O' you could get a tourist visa (SETV) which would give you 60 days. You could then extend that by 30 days (tourism) or 60 days (visit your child) or possible both.