Brown Bay
Brown Bay can only be reached by boat or by a 3/4 mile hike along Brown Bay Trail. In addition, it is a poor place to anchor, so larger boats rarely choose to visit Brown Bay. This of course means that there are often only a few people, and those few enjoy a privacy not found on St. John's more popular beaches.
Shade is plentiful, the cool breeze that's usually blowing makes this a great spot to come for a swim or just to relax by the ocean. It's an ideal spot to stop at while hiking around the many trails on the island.
Ruins
Some of the largest ruins on St. John are found at Brown Bay. They can be reached via the western end of the island. The ruins include an estate house, a sugar factory, horse mills, a storage building, a well, and more.
Snorkeling
The water stays fairly shallow as you move away from shore, and on less calms days this can cause problems for visibility as the bottom gets stirred up. As you move further away from the beach, the water deepens to around 20 feet. Along the eastern side of the bay, there is a bit of a reef that will probably be the best bet for seeing a variety of sea life.