Having been diving around St. Thomas on many visits to the in-laws, I agree with either of these choices. Call ahead to make sure your schedule works.sjspeck:On St. Thomas, Blue Island Divers is an option since they'll pick you up at WICO - the main cruise dock. Or if you dock at Crown Bay, they're located there. www.blueislanddivers.com
Options were just discussed in this thread:
http://www.scubaboard.com/showthread.php?t=158687
Chris Sawyer's also dives around the cruise ship schedules, but they're 20 min. away by cab in Red Hook. http://www.sawyerdive.vi/
If your cruise dive is Coki Beach, you'd be right in passing on it imo.
If Coki is your only option - skip it.
Cheers!
Dunk