King Felipe VI's oldest daughter, who turns 18 in October, will attend the Spanish army's General Military Academy in the northeastern city of Zaragoza during the 2023-24 academic year, Defence Minister Margarita Robles said.

The heir to the Spanish throne will then spend a year at a navy school in the northwestern region of Galicia and a year at an air force school in the southeastern region of Murcia, the minister told a news conference.

The Royal Palace believes she "must receive military training, as her father his majesty the king did, and as is done in other parliamentary monarchies," Robles said.

"In recent years we have made a significant effort to incorporate women in the armed forces," she added.

Princess Leonor is expected to complete two years at the UWC Atlantic College boarding school in Wales at the end of May, graduating with her International Baccalaureate.

If she follows in the footsteps of her father, she will attend university in Spain once she finishes her military training and then complete a masters abroad.

King Felipe studied law at Madrid's Complutense University then obtained a masters in international relations at Georgetown University in Washington.

Spain's Royal Palace said "it is a widely observed and shared tradition in European parliamentary monarchies that future heads of state develop a miliary career."

It recalled in a statement that under Spain's constitution, Princess Leonor will become the head of the armed forces when she ascends the throne.