Hi chaps, I'm new to krabi (Living on koh Yao Noi) and want to change my 1 yr thai driving license to a 5 yr. Originally obtained from Phuket but now I'm being told by Phuket immigration they won't give me a residency letter to renew in Phuket because I've changed address and I now come under Phan Gna. So after googling DLT Phan Gna and Krabi I' m drawing blank on where to go for the residency letter and license renewal. Has anyone done this procedure already and can fill in the gaps please? Much appreciated.

http://www.immigration.go.th/

You will have to get your residency letter for here. They may have an answer to the other question.

Go to immigration in PhangNga Town. Get your COR there. Then go to the DL office in PhangNga Town. All easy and the best time for DL is normally 12.00-13.00.