Loei - Travel Info 

Air-conditioned buses from Bangkok's Northern Bus Terminal leave morning and evening. The journey time is about 10 hours. From Phitsanuloke, in the northeast, catch a bus to Lom Sak where you can pick up the bus on to Loei. Total journey time takes about 6 hours. 

There is a regular bus service between Udorn and Loei that takes about 4 hours.