Buck Island is a small nature reserve just a few miles north of St Croix. You can anchor at the island provided you have a (free) permit from the US National Park Service. Permits take a few days to come through, so you should apply for one as soon as you arrive in St Croix.
The anchorage is next to a sandy beach, tucked in beside the reef. A beautiful spot, worth the effort of getting the permit, although it can be noisy at the weekend when the locals turn out to party.
There is a nice walk across the island, up to a lookout point where you get a good view of the barrier reef.
Buck Island, looking north from the eastern end of St Croix
View of the beach from the anchorage
The barrier reef from the lookout point
The Turks Cap cactus is native to the Virgin Islands and apparently has delicious pink fruit (alas we didn’t find out until later)
Racing the schooner Roseway back from Buck Island