Princess Leonor has now started her studies at the General Military Academy of Zaragoza, where she will reside on campus with other students and will spend three years, completing army, navy and airforce training.
In pictures shared on Friday of her first day at the institute, the royal was seen in full khaki clothing as she carried out studies and practical drills. One photo saw her taking notes, while others showed her and classmates working on fitting a utility belt, while another images showed her in full military uniform in the sun with the Spanish ensignia across her arm.
All the photos were captioned the same from the military instiute, with a message that read: "SAR the Princess of Asturias, on her first day at the General Military Academy in Zaragoza."
The princess is following in her father King Felipe's footsteps, who undertook his own military training, before obtaining a Law degree at the Autonomous University of Madrid.
The teenage royal was dropped off at the academy earlier on Friday morning by her parents, Felipe and Queen Letizia, and it was surely a bittersweet moment for the Spanish royals.
Felipe, 55, was dressed in military uniform while his wife, Letizia, 50, wore a neutral linen trouser suit as they posed for photographers with Leonor and their youngest daughter, Infanta Sofia, 16.
Leonor, who carried a large wheel along suitcase, looked smart in a pale blue shirt and white trousers, while her younger sister Infanta Sofia matched in the same colour hue of jeans and a green patterned top.
It's also been a big time for Sofia, 16, who is due to finish her high school education at Santa María de los Rosales school during the summer. Back in May, she marked her confirmation in a ceremony at Asunción de Nuestra Señora Church in the municipality of Aravaca in Madrid, Spain.
Her confirmation came just days after Leonor's graduation from UWC Atlantic College in Wales, with the Spanish court sharing touching family selfies from the ceremony.
SEE: Infanta Sofia of Spain, 16, rocks cutout dress on a night out in Mallorca - see her trendy outfit
MORE: Queen Letizia steps out with her lookalike daughters during summer holiday
