We were on the June 2nd Eastern, and we did the Secret Sands excursion at St Thomas and loved it. We did the one first thing in the morning, and it was perfect. We boarded some open air buses and drove to the far side of the island. It was interesting, and sometimes sad, to see the condition of the island outside of the port. When we got to the beach, it is a public beach, but we were the only ones there. They had a gentleman waiting who had set up chairs for us, and had drinks and snacks (and rum punch) available for everyone. There wasn't a lot of shade, but we were able to drag our chairs over under a tree to get some -- which was great. My sons (ages 13 and 9) loved swimming at the beach. We found a huge Conch shell, with a resident still living inside, and they also found some tide pools further down the beach that had hermit crabs and other small living creatures that they really enjoyed.
On the way back to the ship they drove to an overlook where we were able to get an amazing view of the islands and the ship. My kids thought it was the best excursion they had taken, and we all had a great day.
Also, the beach has a wonderful restroom with full showers, which was great for getting the sand all washed off before heading back -- so we could head straight to shopping.