We just got back from our honeymoon (ok, about a month ago, but still) and it was awsome!  We went on a Princess cruise to the western Caribbean and did scuba at every stop!  We went to Princess Kays, Bahamas, Ochos Rio, Jamaica, Grand Caymond, Grand Caymond Islands, and Cozumel, Mexico.  We did one dive to 45 feet in the Bahamas, two in Jamaica (one reef dive to 40 feet and one ship wreck dive at 40 feet), two dives in Grand Caymond (one was the North Wall reef dive where we went to 110 feet and the other was Sting Ray City where we fed and pet Sting Rays), and three dives at Cozumel (all 3 were reef dives down to 90 feet).  At Cozumel we saw several Barricuta, one of which swam a foot and a half from our face, and a 4-5 foot gray reef shark swam by under us about 10 feet below.  The whole trip was amazing, and I would recommend Princess Cruise line to anyone!