Most islands will have activities not restricted to indoor kids' clubs. They combine group snorkelling, scavenger hunts, beach Olympics, hermit crab races, sunset activities such as bonfires with roasted marshmallows, pyjama parties, and movie nights.
If you want to start letting your kids learn to dive, select an island that allows the PADI Bubblemaker preparatory course for diving. For older kids, some resorts have rock climbing, painting studios, gaming centres, and teens clubs to keep them busy.