Labadee IS beach time, although you can do other things like the new zip line. or just wander around. One doesn't need to know how to swim to do Dunn's River Falls in Ocho. The falls are very shallow. In Grand Cayman...the Turtle Farm and a general tour of the island would work. On Cozumel...lots of tours that don't involve swimming. But you know, you can do the dolphin encounter without knowing how to swim. You have to wear a life vest anyway (no exceptions....even for people like me who are expert swimmers), and you are standing on a platform that is just 3 feet underwater.