I recently travelled from Udon Thani to Vientiane. It was a pretty good trip and fairly easy, as I had been driving around Isaan in a rented car already. Making the trip to Laos was pretty straightforward. We drove to Nong Khai, to the Friendship Bridge. Once there, there’s a bus that takes you to the Thai border checkpoint. Pass through immigration, then catch a minivan to the Laos side.
Now, the Laos side. If you don’t have a visa, you can get one at the border. From what I have read, it’s best to get an e-visa before you go (get it here. *Important side note: get it from the official site. there are e-scams online). If you decide to go on a whim, no worries. If you carry a couple passport pictures, it will make life easier however even without you can still get it done. They have a variable price list based on the country you’re from. Although e-visas are only $30.00, I believe the price at the border was closer to $35.00 USD, when paid in baht. Some people allege the border prices are “elevated”. I have no ability to confirm that. They have an office with many people in there and the price is what it is. I try not to waste time thinking about or worrying about things I can’t change. Believe me, this saves a lot of aggravation traveling in Asia.
The worst part of visa on arrival was the wait. It took between one and two hours to be processed and that really ate into our day trip. At that rate, we really would have benefited from staying a night. As it was we had a terrific lunch, a perfunctory tour of 3 of the top 5 sites, an overview of Vientiane, and very little else before trudging back over the border. I will need to follow this trip up with a multi-day “soak in the culture” trip where I do a short tour followed by random walkabout.