It's not the prettiest bay on Phuket. It's where you will find the main embarking wharfs for the boats going to neighboring islands such as Koh PhiPhiand also for diving excursions, for those of you who like sporting vacations. You'll also find recreational craft there because the bay is sheltered from the wind.
In short, it's not a place to stay to go swimming and laze around. Chalong Bay is a lively spot, with lots of barsand restaurants along thejetty which are usually heaving with bus loads of tourists who have come back from watching the sunset over Promthep Cape, not really my cup of tea!
Otherwise, apart from the beach and the bars and restaurants, there is Phuket Zoo not far away and, curiously, a rum distillery. Just so you know, it's run by French people!