How long before do I need to book the bus If I wish to travel from Udon Thani to Bangkok?

Thanks

Ian

Depends which bus you want . many companies and many classes of travel. Personally I would book early , perhaps a week before ( especially if its a holiday ) that way you can choose your seat.

My sister-in-law does the bkk-ud-bkk once a month and she uses Nakhon Chai Air bus service. Their terminal is in front of the military hospital.. They do pick-up passengers at the downtown bus station. You can chose your service class and schedule, except for the holidays, try to make your reservation a day or two in advance.