This info is 4 years old mate. it's called Mo Chit BTW

You can get a VIP bus from BKK(Mo Chit) to Udon with Chan tours, 520 baht, I think they run two a day, 1 a 11:15 am and then one in the evening. Takes around 8 hours, but they give you food and drinks, there are personal TV screens but the movies are all in Thai, they have electric reclining seats, with massage so I manage a few hours sleep.
from Mo chit there are VIP32 and VIP24.. thats the amount of seats, i found the 24 has loads of leg room, its really good.. however if your arriving at swampy, you can get an airport bus that takes you to the airport bus station and get a bus to udon, all buses take about 6-7 hours.. are airconned and your given a blanket to sleep under!!

buses are usually every hour or so and at mo chit there is a choice of companies.. i have only taken the night bus either way and slept so i cant comment on the day bus..
Can be a bit of a Hairy Ride on some Tours, i recommend keeping your eyes closed.. )( ....fastest things on the roads these buses. ***** But better in Daylight Hours imo.
and yes the bus will stop.
That's so you can change your Undies !!


I used the Suvarnabhumi Airport to udon service a month ago; you just use the free airport shuttle service to the transportation centre and walk down to the ticket office, buy your ticket and the bus stand is only 30 metres away, by the entrance to 108 shop (like 7-11). Bus is mustard yellow in colour and fairly new, has 825 in service number and says destination Nong Khai (and Udon i think). time: 8pm and 9 pm. not certain about daytime services, but these times fit in with many planes which arrive around 6-7pm. you get blanket, water, snack and maybe milk. Driving standard good, bus usually half full or less, can get some sleep (i take inflatable travel pillow). Only problem: 9pm service arrives in Udon at about 5:15am, not much open then. Cost 418 baht.

Return service a bit more problematic: english signs few and far between at Udon central bus station. But buy your ticket at one of the offices to one side of the bus station (south side, office nearest main road). Only one service i think, at 8:30 pm; leaves from stand 5. The yellow colour and sign on front saying 'Suvarnabhumi' will tell you that you have the right one (also 825 service). Arrives at Suvarnabhumi transportation centre around 4:45 am; shuttle services start at 5:00am i think. This means fits in with most early morning flights with some time to spare.

I am told there are no VIP coaches running this route. But anyway service is quite good and will use again.
http://www.udontalk.com/forum/viewtopic.php?f=37&t=278