We did the walking tour of Nassau (our own made up primarily from Frommer's) and the glass bottom boat that leaves from the same pier where the ship docks.
My then 13 yo LOVED it. It goes over a reef or two and a shipwreck and was cheap.
CarnivalSensation February 2015
Carnival Dream November 2015
Carnival Fascination April 2014
Carnival Elation March 2011
Carnival Imagination Sept 2007
Carnival Sensation Dec 2006
RCI Sovereign of the Seas Sept 2006
Carnival Miracle Sept 2005
Carnival Glory Sept 2004
Carnival Fantasy Jan 2004