Princess Leonor had an early introduction to the military school she will join next month, after completing her higher education.
The princess, 17, accompanied her parents, King Felipe, 55, and Queen Letizia, 50, as the Spanish royals presided over the act of the delivery of employment dispatches and appointments to the new officers of the Army at the General Military Academy in Zaragoza on Friday.
Leonor looked elegant in a white and black polka dot top and skirt co-ord by Spanish label, Barey, for the outing, while Letizia opted for a white waistcoat and skirt ensemble by Felipe Varela.
The princess, who turns 18 in October, will begin three years of training at the General Military Academy in August, the Spanish royal court confirmed earlier this year.
Leonor graduated from UWC Atlantic College in May after completing a two-year International Baccalaureate programme.
Speaking at an awards ceremony in Girona, Catalonia, earlier this year, the future Spanish queen said: "I have just finished high school and I am about to start a new stage with a period of military training. I am happy because I know how much the Spanish value our armed forces . . . it is an important moment in my life and I feel very excited and determined to continue learning and giving my best effort."
Meanwhile, King Felipe and Queen Letizia's youngest daughter, Infanta Sofia, 16, will follow in her big sister's footsteps to study at UWC and move to the UK this summer.
UWC is set within the stunning 12th century St Donat's Castle on the southern Welsh coast, that has often been likened to the fictional Harry Potter school, Hogwarts.
Campus facilities include a library, woodland, an indoor and outdoor swimming pool, and classrooms within historic buildings.
It's popular with many of the European royals and alumni include King Willem-Alexander of The Netherlands, and his middle daughter, Princess Alexia, as well as Princess Elisabeth of Belgium.