7. Oasis of the Seas

This 5,400-passenger Royal Caribbean ship may not have a marina, but it still has extensive onboard water sports programs. Scuba instruction is available from PADI SeaTrek Dive instructors, who teach classes for both beginners and those who need a refresher course in the ship’s sports pool, where you can also play water polo or swim laps (a rarity at sea).

Make a Splash: Have a hankering to hang 10? You can learn to surf on the ship’s two FlowRider simulators, where an instructor guides you until you are ready to ride the waves on your own. The simulator is complimentary, or you can pay for longer lessons.