When it comes to packing, light, loose-fitting clothes are best; pack a few long-sleeved shirts and light pants for the evenings, especially in the winter. Some elegant restaurants have dress codes that require slacks and button-up shirts for men, and dresses for women. You will probably sweat a lot during the day, so plan on at least a few extra changes of clothes. Launderettes are easy to find, but if you don’t fancy doing laundry consider bringing clothes you can wash in the bathroom sink.
Virgin Islanders tend to dress neatly. If you are going to attend a business function you will need smart office clothing: a tie for men and a suit for women. Around town, you will want to look presentable, although casual is fine. Short-shorts and skimpy tank tops are best saved for the beach. After dark, you may wish to dress up, especially if you are going to soak up whatever nightlife there is on your island. Leave your best jewels at home; there is no need for them here, and you are just inviting trouble.
If you plan to do a lot of swimming, snorkeling, or scuba diving, bring two bathing suits; there is nothing worse than putting on a wet suit because you forgot to hang it up to dry the night before. Water booties, aqua shoes, or similarly water-happy sandals are handy, too. Fast-drying shorts that you can get wet comfortably are also very useful, especially if you’re going to be entering and exiting dinghies and small boats. Bring a comfortable pair of shoes you can wear on the streets of historic Charlotte Amalie  or the hiking trails of St. John . A pair of sandals or flip-flops is indispensable. Scuba divers and snorkelers do not need to bring their own gear; there is plenty available for rent around the islands. If you’re going to be camping, pack raingear, insect repellent, and a flashlight.
Be sure to prepare for the sun: Bring lots of sunscreen, sunglasses, a wide-brimmed hat, and lip balm with sun protection. A refillable water bottle is especially handy. If you’re going to be on a boat or near the water a lot, consider leaving your expensive digital or film camera at home and instead bringing a few disposable waterproof cameras. Nothing ruins a camera quicker than saltwater and sand. If you are interested in birds, plants, or marinelife, bring an identification manual with you.
The beach is a great place to catch up on your reading, so don’t forget a few books. You can always trade them in at book swaps around the islands when you’re finished.