Do NOT sign up for the PMK airport shuttle. It's tempting because the rate is a third of what a taxi will cost but the shuttle service is an absolute scam. It took 2 hours for my husband and I to fly from Chiang Mai and 2 hours to get from the Phuket airport to our hotel in Kata Beach.
There is a desk for the PMK shuttle right outside the airport, where you pay and receive a ticket with your destination. They will not leave the airport until every inch of the shuttle van is occupied. We were told we were leaving in 10 minutes, but it took about 30. There is no communication between the driver and ticket coordinator, and the driver does nothing to keep track of where all of the passengers are headed.
We were told we'd be taken directly to our hotel but 20 minutes or so after leaving from the airport, the driver pulled up to a tourism office and all passengers were asked to step out of the van for ticket "validation." What really happens is that everyone is pressed to sign up and pay for various tours and hotels before getting back on the road to your intended destination. It was absolutely infuriating. The driver got out of the van, and joined us in the office, where he sat down and made himself comfortable for 20 minutes.
Pay for a taxi or make other arrangements. The PMK service is totally shady and a horrible way to start any visit to Phuket.