It’s going to cost between 2500 and 3000 and you can just get it on the spot from the Transportation desk in the Arrivals hall. No need to book ahead.
How long does the transfer take?
Probably around 3 hours.
For the way home we booked online with Krabi Shuttle prior to the trip for the journey back to Krabi Airport. Online booking was very easy.
But online booking is not necessary and probably more expensive. There are always cars and drivers available.
Putting this here in case others are wondering - Boss Taxi quoted me 2500 baht and Krabi Taxi quoted 2490 baht per way max 5 passengers.
@Bill2p - you believe we are fine not booking ahead and just telling a driver at the airport we'll pay 2500?
You just go to the transportation desk and they quote you a rate and get you a taxi. You don't have to bargain with the driver. Since 2500 does seem to be the going rate, and you can get it with pre-booking, then probably you should go ahead and book it.