Yeeesssss! This is what you are planning your carribean vacation for, isn't it? This is a world-class sandy beach with crystal-clear blue carribean water. There is even an underwater snorkeling trail at Trunk Bay, maintained by the St. John Virgin Islands National Park, with under water signs. It can be closed on occasion, when the surf is considered too rough. You can rent out and/or reserve those pavilions in the photos below for larger parties
St John - Trunk Bay
This place has it all. The lifeguards, the food and supply shops, a large amount of showers and facilities. The St. John island bus will stop here, but there are always taxis available in the parking lot. As if this wasn't enough, there is another awesome beach just around the bend at Cinnamon Bay, which also has camping sites.