Chalong is the main gateway to the southern end of the island. From Chalong Circle five roads lead out: north to Phuket (ChaoFa Rd East and ChaoFa Rd West which goes past Siam Safari and Wat Chalong), east just a bit to Chalong Bay, south to Rawai and Nai Harn and west past the BaanChang Safari and PaintBall/Shooting Range/Cobra Show and across the mountains to Kata/Karon.
There is a main pier here as well as an Immigration Check-point for incoming yachts. Many of the dive operators depart from here.
Chalong is a centre for many of the resident expats on the island and has the flavour of a combination Thai-European village. There's a great local early morning market and in the evening near the circle is a vendor market featuring all sorts of curries and Thai foods. Local buses heading to all points of the southern end of Phuket pass around the circle and there's a motorcycle taxi stand there as well.