Yes, in South Carolina this card is known as the South Carolina Boater Education Card and it is required for any person under 16 years of age, in order to operate a motorized boat or PWC without restrictions.
Most other states and most of Canada’s provinces and territories also require boaters to carry a Boater Education Card, more commonly known as a ‘Boating License’. Get the Card, even if you aren’t required to in Florida, and you’ll be good to go boating in most of North America.