The first visit to Spain’s American colonies by a member of the Spanish crown was by the Infanta Eulalia in 1893, more than 400 years after Columbus first "discovered" the islands in the name of the crown. ("Infant[a/e]" is the title given to all children of a Spanish monarch, regardless of age, who are not on deck for the throne: that one gets to be Prince/ss of Asturias) If we’re being cynical, it does seem like she only stopped in Cuba and Puerto Rico because she was on the way to Chicago for the World’s Fair, and it would have been kind of impolitic if she hadn’t.

Eulalia arrived in Havana to a “city all in fete,” on May 9, but that would mark the first, last, and only time a member of the Spanish crown visited their American colonial holdings. Soon, the Spanish-American war would divest Spain of even these last vestiges of an American empire that had stretched from Canada to Tierra del Fuego.

As to why they didn’t visit, well, why should they? A monarch need not visit every place they govern, and indeed often could not. As a point of comparison, the first visit by a reigning English monarch to the US was in 1939, when King George VI embarked on a notoriously unsuccessful charm offensive to convince the American public to support intervention in what was swiftly becoming WWII. (Fun fact: The first visit by a foreign head of state to the US was actually King Kalakaua of Hawaii, who was here on sugar business).

I will speculate a little now, but I think they never visited because it was hard, dangerous, and served little purpose.

We should remember that the great bulk of the time Spain was a colonial power, transatlantic travel was far from easy. It required not only vast expenditures of time, but the danger of shipwreck, piracy, mutiny, and so on during a long and isolated sea voyage surely soured the idea in the minds of many monarchs. Even when Eulalia sailed to America, it took weeks.

In a time when the speed of communication was limited to how fast a person could physically carry a message to another person, location of the monarch was often of political significance. Smart monarchs either took their throne with them, or stayed close by. Coups have been started over a shorter absence than a transatlantic journey during the Age of Sail.

I also think it would have felt symbolically dissonant to the contemporary ideas of European royal dignity to go visit the “barbaric” (and often genuinely unsafe) colonial holdings. Under mercantilism, the colonies were little more than wealth extraction farms. But I admit to being on less firm footing here, when it comes to sourcing such ideas.

Sources:

Wilson, R.E. (1966). The Infanta at the Fair. Journal of the Illinois State Historical Society

Eulalia. (1937). Memoirs of a Spanish Princess.