At first he studied piano and voice with Magda Prunera, the mother of one of his childhood friends, and at the age of 8, he also started taking music lessons at Barcelona's Municipal Conservatory.
At the age of 8, he also gave his first public performance, singing 'La donna è Mobile' accompanied by Magda Prunera on the piano, on Spanish National Radio. A recording of this still exists and can be heard on the video biography, José Carreras – A Life Story.On 3 January 1958, at the age of 11, he made his debut in Barcelona's great opera house, the Gran Teatre del Liceu, singing the boy soprano role of Trujamán in Manuel de Falla's El retablo de Maese Pedro. A few months later, he sang for the last time as a boy soprano at the Liceu in the second act of La Bohème.
Throughout his teenage years, he continued to study music, moving on to the Conservatori Superior de Música del Liceu and taking private voice lessons, first with Francisco Puig and later with Juan Ruax, whom Carreras has described as his "artistic father". Following the advice of his father and brother, who felt that he needed a 'back-up ' career, he also entered the University of Barcelona to study chemistry, but after two years he left the university to concentrate on singing.
1970s and 1980s
Juan Ruax encouraged Carreras to audition for what was to become his first tenor role at the Liceu, Flavio in Norma, which opened on 8 January 1970. Although only a minor role, the few phrases he sang caught the attention of the production's leading lady, the eminent soprano and fellow Catalan, Montserrat Caballé. She asked him to sing Gennaro with her in Donizetti's Lucrezia Borgia, which opened on 19 December 1970. It was his first principal adult role, and the one which he considers to be his true debut as a tenor. In 1971, he made his international debut in a concert performance of Maria Stuarda in London's Royal Festival Hall, again with Caballé singing the title role.