Welcome to cruise-chat. Sorry no one responded sooner to your question. Trunk Bay is beautiful and the snorkel trail is pretty neat - but it can get very crowded with cruise ship excursions. If snorkeling is your number one priority in St. Thomas, Buck Island and Turtle Cove offer excellent snorkeling. If this is your first time in St. Thomas, you might want to consider snorkeling at the beach next to Coral World.
I had forgotten where I found this site and just found my way back. Thanks for the info. I would be interested in hearing more about Buck Island. Can you do this on yor own or do you have to book it through the cruise line?
That is a good question. I know there are numerous charter companies and private tour operators that run out of St. Croix, but I am not positive about St. Thomas. I will try to find out and report back or perhaps someone else on the board knows.
Snorkeling at Coki Beach in St. Thomas was also quite spectaculr. It is located next to Coral World which is essentially an underworld aquarium and has similar coral and sea life. I was quite impressed and I have previously snorkeled at reefs in Bermuda, Chanakanaab Park in Cozumel and the Lagoon in Cancun.
Trunk Bay is beautiful, however, there are some great catamaran and sailboat trips to Buck Island with some snorkeling there. You can take a water taxi to Trunk Bay for about $6.50 per person then a taxi to the beach. The last time we were there is was $5.00 per person and you can rent a locker. It is really a toss up because both types of snorkels are great.