The Gulfstream G450 business jet took off from Abu Dhabi in the morning.
After almost two years, Juan Carlos I returns to Spain.
The emeritus monarch does not end up in the capital Madrid in the evening with the inconspicuous business plane, but in Vigo in north-west Spain.
On August 3, he secretly escaped from the port city's small airport so as not to be a burden to his son Felipe.
Hans Christian Roessler
Political correspondent for the Iberian Peninsula and the Maghreb based in Madrid.
Follow I follow
In Spain, all investigations against Juan Carlos, who has also paid part of his tax debts, have now been dropped.
It was about the suspicion of corruption and tax evasion.
Still, it will only be a brief visit to the country of which he was king for almost four decades.
No overnight stay in the palace
Only on Monday will the 84-year-old monarch stop by the Zarzuela Palace in Madrid shortly before his return flight to the Gulf to meet his son Felipe and his wife Sofía, whom he has not met since leaving for voluntary exile.
The ruling left-wing coalition had made it clear that spending the night in the palace on the outskirts of Madrid, where Juan Carlos lived for many years, was out of the question: it was not a private residence but the official seat of the Spanish head of state.
Prime Minister Pedro Sánchez and other members of the government are demanding an apology from Juan Carlos for his financial and personal affairs, in which he has been far from exemplary.
Only to his son Felipe did Juan Carlos regret his wrongdoing "with all his heart" in a letter in March and announced that he would not live in Spain again, but only wanted to visit his homeland from time to time.
Many Spaniards saw his departure for the Gulf as an escape from his judicial responsibilities.
Only his daughters Elena and Cristina and their children visited him at his luxury resort on the Gulf.
“Juan Carlos has already undone all the merits that the Spanish people have given him.
The monarch is unaware of the harm he is doing to the monarchy.
He comes to Spain, but not to explain or apologize," said well-known columnist Àngels Barceló on Cadena Ser in the morning.
Even the conservative newspaper "El Mundo" accused him of a loss of reality in an opinion article with the headline "Don Juan Carlos, not like this": he had "turned everything around him into a circus".
He can be sure of the greatest attention as soon as he arrives in the Galician seaside resort of Sanxenxo on the Atlantic coast.
Mayor Telmo Martín is looking forward to seeing him and announced that he will show him "the affection that we feel for him".
The marina bears his name there.
After Sanxenxo, Juan Carlos, even before moving to Abu Dhabi, had increasingly taken refuge in the house of his rich sailing friend Pedro Campos;
he will also be a guest there this time.
The sailing regatta in the six-metre class, in which he himself took part as a helmsman until 2019, starts there on Friday.
It was not yet clear whether he would take the helm of the “Bribón” himself, with which he won the world championship.
He could, however, ride on an escort boat.
Juan Carlos is fit, but he has not trained for almost three years, according to those around him;
In 1972 Juan Carlos competed at the Olympic Games in Munich.
Although it is not one of the most important competitions, hundreds of media representatives have been accredited.
The next regatta is scheduled for June on the Galician coast.
In Spain, it is not excluded that Juan Carlos could be back - as another stage in his gradual rapprochement with his country, where he will not settle for the time being.
However, the 84-year-old had already let his son know that he "did not want to die far away".Keywords: