One of my kids has dual passports, the Thai one is expiring in mid Sept 2013, the other passport has until 2015.

If we traveled o/s in June and returned in mid August, would there be an issue departing on the Thai passport with less than 6 months ?

She would be departing Thailand on the Thai pp and entering the destination country on her other passport.

I know the logical answer is to get her a new Thai pp before departure, but we may not be able to do that before departure due to one parent not being here to sign the documents required.

No problem, you cannot leave Thailand on a Thai expired passport but a Thai can enter on a Thai expired passport.

Since the airlines are the only ones that would question the amount of time left on the passport (rules for the destination country) showing their other passport along with the Thai one would take of that matter when checking in for the flight.

Immigration would not be concerned about the amount of time left on the passport.

The passport office will accept notorised consent from the other parent for anyone in a similar position.

HTH

Correct, both must sign but no neeed to both appear in person.

However, in this case there is no problem to get a new passport after they return.

The other possibility is that if the overseas destination has a Thai embassy, you could simply get the passport replaced there while you are overseas - assuming you would be near the embassy for long enough (usually a few days depending on the country).

Thanks for the info

It's probably late in the game for you now, but out of curiosity, did the Thai parent call the passport office and see if both parents have to sign? I never signed anything when my kid renewed her Thai passport. My wife is also a dual and for the US side, definitely both parents, but I don't recall it being needed on the Thai side when one parent is a Thai citizen.

Please note if you live out towards Central Bangna, there is a passport office in that building.

It's probably late in the game for you now, but out of curiosity, did the Thai parent call the passport office and see if both parents have to sign? I never signed anything when my kid renewed her Thai passport. My wife is also a dual and for the US side, definitely both parents, but I don't recall it being needed on the Thai side when one parent is a Thai citizen.

Please note if you live out towards Central Bangna, there is a passport office in that building.

No, she did not call.

But the missing parent is the Thai one, so kind of irrelevant.