AirAsia flies BKK (Suvarnabhumi) to Udon Thani 3 times daily: 7:25, 11:05, and 17:10
Promo rates can be found as low as 800 baht (24 U$D).
Keep in mind that you need to add VAT, airport taxes, and baggage fees as we assume you are bringing more than carry on. You might be looking at 1500 baht by the time you are ready to pay.
Once in Udon Thani, right before you exit the airport, you will see on your right a window that reads "Limousine Service" to Nong Khai.
The fare is 200 baht to Nong Khai, and 150 baht if you are taking the limousine the other way around.
With the ticket in hand, you exit the airport and you will bump into a bunch of shuttle drivers that will direct you to the right van.
Once in Nong Khai, the shuttle will head straight to the Friendship Bridge as most people in it will be crossing the border to Laos.
STAY IN THE VAN.
The driver will then ask you where are you heading.
Ive noticed that most drivers do NOT know where Isara is, added to the fact that you won't pronounce it the proper way, and so forth.
The easiest way i've found is to tell them you are going to the Hospital.
Every van driver knows Mee Chai Rd, and the hospital are.
In Thai, you might wanna try "long payaban nong khai" which stands for hospital.
If you make it to the Hospital, you are a block away.
Stand at the hospital's door as if you were exiting the building, and walk to your right.
Isara will be at a block and a half distance on your right.
If you fly into BKK anytime after lunch, and before 7:30pm, there is an Express overnight bus that leaves straight from the airport.
The fare is 432 Baht, it departs at 8pm from the airport.
(BEWARE its advertised as 9pm, but that is from the airports remote bus station. If you are taking it AT the airport it is 8pm)
Once you go through customs, get yourself to the 1st level at the airport.
The counter says "Patayya" but they sell the tickets to Nong Khai there as well.
The good side about the bus is that on top of being a third of the price, there is no extra fees for baggage.
The bus will drop you off at the Nong Khai Bus Station sometime around 8am.
You can possibly arrange for someone from Isara to pick you up, or you can take a Tuktuk following the same directions as "By Flight".
-- Directions on the Train, and other bus services Coming Soon! --