umm.. i dont think so.. you can go to a local dive shop in your town and get it though b4 the cruise.. im a certified scuba diver and thats how i got it.. but u can take dives w/o being a certified scuba diver.. they have certain dive programs where u go to a 30 minute class then u dive with an instructor.. so that is a possibility too
umm.. i think only certain ones.. i know cozumel does.. but u could call the cruise line and ask them.. in your excursion booklet though.. look for beginner scuba diving or something along those lines.. it should be in there