Buses depart from Chiang Mai throughout the day, and are available as either a bus or mini-bus. The buses cost 95 baht, are fairly cramped, fan only, and take about 6-7 hours. The mini-buses, in contrast, cost 250 baht, have much more comfortable seats, air-conditioned, and take 4-5 hours. The schedule for the two are as follows:
Minibus: 06:30/ 07:30/ 08:30/ 09:30/ 10:30/ 11:30/ 12:30/ 13:30/ 14:30
Regular bus: 7:00/ 9:30/ 12:30