So the prince of wales is a title given to the heir to the British throne. He has only become prince of wales now that his father is the reigning monarch.
Duke of Cambridge was a title bestowed on him by the queen as a wedding present.
While Wales was the family name both William and Harry used when needed, for example during their military service, Prince William has never been titles the Prince of Wales before now.
Given that he was the son of the prince and princess of Wales though, the confusion is very understandable.
Edit: regarding using Wales as a family name, his last name is actually Windsor, Wales is just kind of a lazy alias.
Latest Answers