The monarch places this coat of arms on a mantle Gules lined with Ermine. Above the mantle is a pavilion Gules again topped with the royal crown.
Upon his succession to the throne, Willem-Alexander adopted the Royal Standard of the Netherlands, which is a square orange flag, divided in four-quarters by a nassau-blue cross. All quarters show a white and blue bugle-horn, taken from the coat of arms of the Principality of Orange. In the centre of the flag is the (small) coat of arms of the Kingdom, which originates from the arms of the House of Nassau, surmounted by a royal crown and surrounded by the insignia of the Grand Cross of the Military William Order.
Quarterly, 1 and 3, Azure, billetty or a lion with a coronet or armed and langued Gules holding in his dexter paw a sword Argent hilted or and in the sinister paw seven arrows Argent pointed and bound together or (royal arms of the Netherlands, i.e. that of his mother, Queen Beatrix), 2 and 4, Or, and a bugle-horn azure, langued gules (arms of the former Principality of Orange), on an inescutcheon vert, a castle proper, on a mount of the last (arms of the House of Amsberg, i.e. that of his late father, Prince Claus).