if you are into adventure stuff, I would recommend doing a rock climbing session at Railay in Krabi. Since you are in Phuket for quite a number of days, you could hop over to Krabi and spend some time there. The natural rock climbing cliffs and the surrounding scenery makes it one of the best places to rock climb in SE Asia.



The rockwall instructors also brought us for some caving before we rappelled down and this was the scene from the top



I did mine with a company called Hot Rock at railay in 2002. I know king's climbers are also quite reputed.