The King's standard in Spain is a square flag, dark blue field with the coat-of-arms in the middle.
On his yachts, the King flies the normal yachting flag, the well bicolour flag with a blue royal crown in the centre of it. He also flies the burgee of his local sailing club ( Palma de Mallorca). Until 1931, the King ( Alfonso XIII, and before him his father Alfonso XII) always used the flag of the Spanish Federation of Nautical Clubs at the stern on the royal yacht Giralda .
The 1971 and 1977 regulations make reference to two flags: the guión —which may be translated as 'guidon' in the medieval sense of 'flag which indicates the king's position'— and the estandarte or standard. The guidon is defined as a very specific flag —with a fringe and fixed dimensions —80cm square, coat-of-arms 44cm high, fringe 22mm wide. The standard is defined as any flag which looks like the guidon without the fringe, within a certain range of sizes, rather than just one size
The Flag of Spain