Chris Sawyer Dive Shop is in the Red Hook area. It is probably the oldest (or one of the oldest) dive shops on the island. Years ago I took my first Experience Scuba class near Coki Beach with them, years later returned as a nitrox certified diver. They are full service. I have not used any other dive shops on the island. Do a search on Google or Good Search for Scuba in St. Thomas and there are other names there as well.