Best bet, is to just grab a cab and head over to Meagans bay, its a beautiful beach, very nice calm waters, only takes 10/15 minutes to get there. If you want, the taxi driver will drop you off downtown on the way back if you want to fit in some shopping.
We have been to St. Thomas twice. The first time we took a cab to Magens Bay. It was 4.50 pp. one way. It was absolutely beautiful. It had a store, a bar and a place to buy lunch. The bathrooms were very old a run down but at least they had them.
That was in 1997. We just got back from a cruise on the Pride two weeks ago and stopped there again. This time we wanted to try Coki beach. We did not like that at all. You can't even compare it to Magens Bay. The snorkeling is the best I am told but that was it. It took longer to get there, $7.00 pp. one way. It was small not well kept. There are people there all over the place trying to get you to buy braids, food, drinks, chairs, umbrellas etc. We will not go back there again.
I am told the best beaches are at the hotels.
I agree with Donnab about Coki Beach, we opted to go there instead of Magen's Bay and I expected it to be quite nice, the only nice part was the weather. Basically I feel our beaches here in Nova Scotia Canada are 100 times nicer then Coki, now Magen's Bay is beautiful.
When we were in St. Thomas a couple of years ago we went to Sapphire beach. It was close to a resort, you could rent chairs and it was beautiful. Not crowded either. We will be in St. Thomas again and think we'll try Maegan's Bay for a little while and then head to Sapphire Beach for the rest of the day. I've heard several say Sapphire is still a good choice.
We had gone to Coki through a ship tour and upon arrival, we found a cab and got the heck out of there, dirty, broken down cars and shacks around crowded, not resort like at all and not our idea of a good time.
We went to Magens Bay in April. We were on the Paradise. The cab ride was $6.00 per person, each way and there is a $3.00 entrance fee per person also. We went in the afternoon and it was nice and quiet. I thought the sand felt like cornstarch. It was so soft. No rocks or shells.