I'm not aware of any designated areas for camping, however there are places where I have seen people pitch tents and hang out over a weekend...like Hull Bay (Western side), or Stumpy Bay...but for visitors, I don't think there are any locations that you would like to use. No fresh water being a major concern.

Marty is correct. There are of course designated campgrounds at Maho Bay and Cinnamon Bay on St John and also a relatively new campground on Water Island but locals who once in a while pitch their tents at either Hull or Stumpy (or Mandahl for that matter) on STT know what they're doing and do a one-night basic camp. Camping on VI beaches outside designated areas is illegal and, as small of an island group as these are, a newbie or visitor attempting to buck the system is liable to be handcuffed and charged in short shrift. You don't want to go there!!! Cheers!