Beachy casual! You can wear pretty much whatever you'd like here. If you are on a boat or on the beach, plan on being in a bathing suit, beach cover, or comfy shorts and a tank top most of the time. A hat and rashguard are essential since you will be in the water and sun a lot. It's rarely cool in BVI, even at night. For a week on a boat, plan on a few swimsuits, some comfy shorts, a couple of tank tops, a rashguard or two, 2 swim coverups, and a sundress.