I recommend. The northernmost (best part) Patong. The beach is interesting. Fine sand and large rocks (mini-rocks). Swimming is convenient. The water is blue and clear, even at depth. There is a cafe nearby, everything is very tasty, cooked at a fairly good level and, in comparison with other places, cheap. From the cafe, Wi-Fi catches almost all over the beach...! Use...!
I really liked the beach. The entrance between the stones is sand. It is a pity that there are few places for swimming, it is better to be closer to Patong. The sand is coarse, does not stick to the feet.