We have been to St. Thomas three times, twice on a cruise and for a 7-night trip to the VIs. We LOVE the VIs both U.S. and British.
Suggestions:
1 - Taxi to Coki Beach and/or Coral World. We did these two places together twice. We went to CW first and got a locker and used their restrooms and showers. We bought burgers and fries there too. It is easy to get a taxi over and back. Look CW up on their website.
Coki Beach
DD#4 on Coki
2 Taxi to Secret Harbour Beach Resort (Check out their website). It is a quiet, private beach, with a dive shop where you can rent snorkel gear.
Great snorkeling, right from the beach.
We swam with a sea turtle every afternoon.
Swimming with our buddy
Sitting in the shade - see our toes?
3 OR THE BEST FOR LAST - Hundreds of cruisers do this EVERYDAY Take a taxi to Red Hook, a ferry to St. John and (a) explore Cruz Bay, (b) taxi to Trunk Bay (c) rent a jeep and explore on your own. There are many wonderful beaches and a lot of people poo poo Trunk Bay for tourist crowds. We went on our own both times and not with a group. It was fine both times tour groups rush in and out and you have a lot of time to yourself. I love Trunk Bay. If I were staying longer I would go somewhere else but is a wonderful place. (A reason to return). I consider St. John Heaven on Earth.
Trunk Bay
Took this one while snorkeling at Trunk