What is the procedure for driving your own car from Thailand to Cambodia?

Don't do it.

Good luck. 7774/all-right-hand-drive-vehicles-banned-definitely-in-cambodia/

Bring your blue book. If the vehicle isn't in your name, must have a power of attorney. New customs app is now used by Cambodian customs but isn't compulsory. You can't even use it unless you have a Cambodian SIM.

This way, you might be able to bring your car in across borders such as Poipet, which otherwise only allow entry for limited local travel or refuse you altogether. However I haven't tested it yet and on my next trip won't risk Poipet until I'm sure the app works as advertised. I might try crossing into Cambodia at Psar Prum using the app (I have a Cambodian SIM that I top up from time to time) though. Previously, I've only exited there back into Thailand.

It's best to enter at O'Smach, Koh Kong (Cham Yeam) or Chong Sa-ngam. The first two are the best for first timers and in general. Chong sa-ngam will definitely work for entry using the app, according to the customs official who guided me through the process when I exited back into Thailand on my most recent trip there. Psar prum, as mentioned, might work too. However, the most trouble free crossing is definitely O'Smach.

If you want to exit elsewhere, make sure you get some kind of paperwork from the entry port. If you don't, you'll need to plead ignorance and there might be an hour long back and forth between customs at your exit port, you and customs at the port of entry. Eventually, they'll let you pass either for free or a small fee.

car must be in ur name and you must bring the book with you>

Thats all<

DO NOT enter at Poi Oet< use osmach, south of Surin or Koh Kong border.