The combined attractions of Leinster Bay and Waterlemon Cay are a snorkeler’s dream. Calm and protected, Leinster has extensive sea grass, with turtles, fish, and sea stars. Waterlemon Cay is home to a healthy and expansive coral reef. Together, they make a good half-day, or even full-day, destination for enthusiastic snorkelers.
Leinster Bay is covered with packed, coarse yellow sand, but shade and calm waters make it a decent place to swim. Put on a mask and snorkel to peer down at swaying sea grass, conch, and other creatures. There is ample shade beneath low-growing sea grape trees. Landlubbers can hike 0.25 mile up the Johnny Horn Trail, which departs from Leinster Bay, to reach great house ruins and nice views of the bay below.
Waterlemon Cay, named for a type of shark, has hard-packed sand on the southern tip facing the shore and rocky edges on the seaward-facing side. Begin at the sand and make a counterclockwise ring around the island for the best snorkeling. In rough weather, don’t attempt a complete circumnavigation, though. Look for squid, fish, and other reef-dwelling creatures. Many people say this is the snorkeling highlight of their trip to St. John [1].
Hiking is the only way to reach Leinster Bay and Waterlemon Cay. The Leinster Bay Trail (0.8 mile) departs opposite the driveway for the Annaberg Plantation [2]. The hike is flat and follows the shoreline. From Leinster Bay, you can swim out to Waterlemon Cay or continue walking another 0.5 mile along an unofficial trail that hugs the shoreline and takes you closer to the cay.
There are no facilities at Leinster Bay; pack plenty of food and water.
Links:
[1] http://www.moon.com/destinations/virgin-islands/st-john
[2] http://www.moon.com/destinations/virgin-islands/st-john/sights/north-shore/annaberg-plantation