I am thinking of making a trip to Isaan during the cool months, may also drive into Laos.

I am looking at the Thai/Laos border crossings at Mukdaham and Ubon.

Can I drive a Thai car into Laos at those two crossings? I have crossed Nong Khai border to Vientiane with my Thai car before so I know all the paperwork requirements.

Also can I enter into Laos at a crossing and exit through a different border crossing?

Why would it be different, it's Laos.

Thailand J: you might be better off just Googling for this info. I had a look now and read this:

 

"Yes, you can drive a Thai-registered car into Laos at the Mukdahan/Savannakhet border and exit at the Friendship Bridge in Vientiane, but it's a multi-step process with specific documentation requirements and cross-border rules. The car must be fully owned by you or you must have a specific authorization document to drive it across the border. You will also need a valid passport, international driving permit (if required for your nationality), and to complete the necessary paperwork for both border crossings, which may include temporary vehicle import permits and visa on arrival for Laos."