Can my Thai gf and our 2 kids get a 2 night permit just with her id?

I know she's OK but do the kids just 'tag along'?

We'll have their birth certs with us.

Cheers. ?

They have to apply for a 3 day border pass. The girlfriends ID card will be enough to get hers. But for the children it will require their house book and/or birth certificate.

At most border crossings their will be an office just before the crossing.

You are right Ubonjoe it will require the birth certificate and the Lao immigration wants 50 Baht as well.

BTW: We went two weeks ago to Laos and my FIL carried our child and he was stopped and they said either the father or mother should carry the boy over.