They are on opposite sides of the Mekong so the buses each side of the Border Control/Bridge will take under an hour in total, I’d suggest. How long it takes you to get through Immigration then catch the (Laos side bus) is another matter?
The one time I did it, they bloody left us behind at Immigration!!!
Nickunj. Just a slight word of warning. When I started teaching, I did a few terms ‘part-time’ as I thought it a good idea.
Unfortunately, what I thought ‘part-time’ work was, wasn’t anything like the Thai’s thought. It was NO less work than a ‘full-timer’, no holiday/sick pay and a lot less money.
Suggest you ensure you don’t get caught out like me.