My wife and I took some local advice and hiked around to the rocky-beach side of Leinster bay, where you can enter the water and swim about 100 yards offshore to snorkel along Waterlemon Cay. This was the best snorkeling we experienced in St John from a beach area(go by boat to get out to some even better spots), because the swim out and depth deters more casual wading swimmers from standing up on the reef. Thus the reef is very much alive and less damaged than the coral around some of the bays that are more popular for casual swimmers and Cruise Ship excursions, such as Trunk Bay. There is a great variety of marine life here, and taking you time is rewarded as you pass around the small island

This leads me to the only warning advice I can give: you really need to go extra heavy on the suntan lotion and/or wear a swimshirt. I normally never burn and have olive skin, but because the sights here are so fantastic, I forgot to reapply and had no swim shirt, and the sights kept my bare back to the sun for over 150 minutes!! Suffice to say, the burn was pretty severe...

Sun protection measures aside, this is a highly reccomended half-day, and the swimming around the sandy part of Leinster bay is nice too.

We planned ahead, and brought snacks and water bottles with us. The water bottles were fine, but after about an hour of snorkeling, we returned to find that the mongooses (Honest, I looked it up. Mongooses is preferred to mongeese) had spirited away our chips and pretzels. Checking the underbrush, we determined that we were not the first victims. Plenty of wrappers.

Biggest drawback is the large number of 3-4 inch stumps, about 1 to 2 inches in diameter that stick up out of the middle of the trail. On the way in, I met a lady and her husband. She had fallen and I'm pretty sure she had a broken arm as a result. The fall was caused by one of the stumps. Be careful.

My favorite place on St. John, it takes about 20 minutes walking from the parking lot, and it does not have an actual beach, but several spots were to put your beach chair. It is very quiet an a short swim away from wonderful snorkeling location. Nice hiking around here too!

Sweet bay if you can get a mooring. The bay is calm and full of fish and turtles (yes you can swim with them). The small island (Waterlemon Cay) at the east end of the bay is teeming with fish and lots of coral and sea fans. But, the current can be a little tricky. You need to be a strong swimmer.