This blog gives you the information how to travel from Nakhonsithammarat Airport to Koh Samui like local people do.
When you arrive at Naknonsithammarat Airport by Air Asia , Thai Lion Air or Nok Air, after you collect the baggage, you have to walk until the exit of the airport and you will see the limousine counter service that can take you to any places in the town or nearby area.
To go to Nakhonsithammarat Town, the join car will cost 100 Baht per person, but you have to wait until it is full then they will go. If you charter a car it will cost 300 Baht per car to Nakhonsithammarat Town. It takes about 15-20 minutes from Nakhonsithammarat Airport to the town.
If you want to go to Koh Samui from Nakhonsithammarat Airport, you can charter the car from Nakhonsithamarat Airport to Donsak Pier that it will cost about 1500 Baht per car, maximum for 4 people in the car (not much space for the baggage, if you have the big baggage and / or much more people, you have to charter the van from Nakhonsithammarat Airport to Donsak pier that will cost you 2500 Baht per way.)
Or if you don't want to charter any car or van, but just want to travel or be transferred like local people in Nakhonsithammarat, just read the next topic.
Update information (12th November 2018)
On 23rd September 2018 Nakhonsithammarat Airport just opened the 2 lines of public bus from Nakhonsithammarat Airport to the town
Line Number 7 : Fom Nakhonsithammarat Airport , driving pass Benjama junction(สี่แยกเบญจมราชูทิศ), then last stop at Nakhonsithammarat Main Bus Termainal(สถานีขนส่งตลาดหัวอิฐ) (Local people call this place "Hua It" (Thai language : สถานีขนส่งตลาดหัวอิฐ) The fare price is 30 Baht per person all along the way, takes about 30 minutes to Hua It bus terminal
Another line is Number 8 : From Nakhonsithammarat Airport, driving pass Tha Pae Market, Om Kai Road(ถนนอ้อมค่าย), Pattanakarn Ku Khwang Road (ถนนพัฒนาการคูขวาง), Naluang junction(แยกนาหลวง), and Last stop at Huathanon Junction(สี่แยกหัวถนน), the fare price is 50 Baht per person all along the way , take about 50 minutes to Huathanon Junction.
Picture Showing the name of the bus company Nakhonsri Airport Bus starts service from 23rd September 2018 onward. Service daily during all flights time. And the contact numbers are shown on the picture too.