Was about 10 years ago that I was there, but did a charter out of the port by Phuket. We caught a heap of skippies, plus a couple of Mahimahi. Really cheap, relaxed, beautiful lunch and a bit of snorkelling thrown in. Was a great day.
Also went out with a local young guy in the longboat style thing, with a Datsun 180B motor on the back. Caught some lives and drifted them around a reef for sail fish, but no takers. Great fun though with a bit of snorkelling thrown in. Would have been good to have some extra gear eg sb or jigs to play with while we drifted.
Great place to spend some time in.