If you want to travel by from Hat Yai to Chiang Mai, you have the options of travel by train, bus or fly.
The distance from Hat Yai to Chiang Mai is over 1,600 km, so if you travel overland, it is best to break the journey and stop off along the way.
This is a long overland journey, so easily the best option is to take an Air Asia flight from Hat Yai to Chiang Mai (HDY to CNX).
The flight time is around two hours and it is easily the quickest way to get to Chiang Mai from Hat Yai.
This long rail journey is possible with two separate train trips:
The first part of the journey is to take a train from Hat Yai Junction to Bang Sue Junction in Bangkok.
Bang Sue is the main interchange station for the South, North and North-Eastern Railway Lines in Thailand.
All trains from Hat Yai Junction to Hua Lamphong (Bangkok's main railway terminal) stop at Bang Sue Junction, around 20 to 25 minutes before arriving at Hua Lamphong.
Once at Bang Sue you can then take another train to Chiang Mai.
Our recommended way to travel by train to Chiang Mai from Hat Yai:
A good option is to take an overnight sleeper train to Bang Sue Junction.
Then take a regular train from Bang Sue to Ayutthaya.
Spend the night in Ayutthaya to see the sights of the ancient capital.
Next take the train from Ayutthaya to Chiang Mai.
There are no direct bus services to Chiang Mai from Hat Yai.
If you really want to do this journey by bus (not recommended), here is how you can do it.
Take a bus from Hat Yai to Bangkok (all buses arrive at the Southern Bus Terminal).
You will then have to get to the Northern Bus Terminal (Mo Chit), where most buses leave for Chiang Mai.
A nicer alternative would be to take a bus or train from Hat Yai to Hua Hin (220 km south of Bangkok).
From Hua Hin there is a direct bus service to Chiang Mai.