Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Belfast to Chiang Mai as you normally would.
For a flight from Belfast to Chiang Mai, you will be flying into Chiang Mai. Chiang Mai (CNX) is just 1.9 mi from the center of the city. Chiang Mai is the only Chiang Mai airport and it handles 0 inbound flights from Belfast per day. 0 airlines have flights to Chiang Mai from Belfast on a regular basis.