In Thailand, in order to be able to drive a rental car on your own, you need to be in possession of a driving license belonging to your native country. This must be a full license and probationary licenses are not acceptable here. In some cases, the car rental company may also ask you to show an international driving permit, which you can obtain from your native country before embarking on your journey in Thailand. For procuring hired cars, you will also be asked to provide the car hire company with a translated copy of your driving license in case it is in your native language which is not English.
While driving through all destinations in Thailand, make it a point to keep both your driving license as well as passport in your possession. With the minimum age limit set as 21 years, few car rental companies may allow younger drivers to drive a rental car, provided that extra fees is paid by the driver before taking the car into possession.