For such a small landmass – 1 mile long by half a mile wide – Buck Island draws big crowds. It’s not so much what’s on top but what’s underneath that fascinates: a 19,015-acre, fish-frenzied coral-reef system, protected as Buck Island Reef National Monument, that surrounds the island. The sea gardens and a marked underwater trail create captivating snorkeling on the island’s east side. Most visitors glide here aboard tour boats departing from Christiansted, 5 miles to the west.

　　Note that in winter the trade winds blow hard at Buck Island, which can result in rough water for newbies to the mask and fins. On the island, pretty Turtle Beach is where endangered hawksbill and green sea turtles come ashore. A hiking trail circles the island’s west end and leads to an impressive observation point.