The Islands in the South of Thailand are even more accessible with daily boat services connecting them. If you depart from Phuket to Koh Yao or Koh Yao to Phuket there is an option of using a speedboat service which connects the Islands daily and all year round weather permitting.
Below is the speadboat timetable, there are many operators offering this service. Tickets can be bought in Phuket or from the Koh Yao Islands from any resort or local travel agent.
The Bang Rong pier in Phuket is found on the estuary of the Khong Bang Rong, a river found on the eastern side of Phuket. It is away from all the touristy attractions and a taxi would be required to take you to and from the pier which your resort can help you organise.