She is the younger daughter of King Felipe VI and Queen Letizia[1] and, as such, is second in the line of succession to the Spanish throne behind her sister, Leonor, Princess of Asturias.

Infanta Sofía was born on 29 April 2007 at 16:50 (CET) at the Ruber International Hospital in Madrid by means of a caesarean section, two days after due date.

[8] She received her First Communion on 17 May 2017 at the parish Asunción de Nuestra Señora, and was accompanied by her parents, her older sister, her grandparents, her maternal great-grandmother Menchu Álvarez del Valle, her step-grandmother Ana Togores, and her godfather Konstantin-Assen of Bulgaria, Prince of Vidin.

[11] Like her older sister, in 2009, Sofía started her education at the Escuela Infantil Guardia Real, the daycare for the children of the Spanish Royal Guard.

At the age of 3, she attended her first event, an official reception at the Royal Palace on the occasion of the victory of the Spanish national football team in the 2010 FIFA World Cup.

[15] In 2021, Infanta Sofía and Princess Leonor participated in their first joint act without their parents, representing the "A Tree for Europe" campaign of the European youth association Equipo Europa.

[16] While her sister was studying abroad, she took center stage by accompanying her parents to different events, such as the 2021[17] and 2022[18] National Day parades and the 2023 Copa del Rey final.