I am aware Thai's do not need a visa for laos however do they need

a passport travelling from Bangkok

Regards Nb

I believe there is provision for day trips using ID card for those from border regions but not sure if it will be honored if her residence in Bangkok. It would be better to obtain a passport if any travel is being planned as they only cost about 1,500 baht.

If a Thai national is flying, then according to Qantas' IATA database, a Thai passport is required. Agree with lopburi3, that it is better to obtain a passport. However, believe that the 50-page Ordinary Thai passports currently costs 1000 Baht plus 5 Baht for taking a photograph. Applications can be made at one of the Passport Offices.