Teaching After his return to Costa Rica in 1916, Fonseca dedicated his efforts to teaching, participating in important academic projects such as the founding of the Conservatorio de Música y Declamación. He was also part of the faculty of the Escuela de Música Santa Cecilia, where he occasionally assumed the duties of the Director of the Institution (J. J. Vargas Calvo) during the director's absences. In 1934, Fonsca founded the la Academia Euterpe with his son Jimmy and violinist Raúl Cabezas. The academy was only in operation for a few years. It primarily focused on teaching violin and piano, but also had a choir and an orchestra. Fonseca was an instructor at the Colegio de Señoritas where he was a professor of music from 1927 to 1942. Finally, Fonseca was a founding professor at the Conservatorio Nacional de Música, in 1942. This institution later transformed into the School of Music Arts of the
University of Costa Rica. a musical institution for whom he composed and released some of his work. He was also a music critic and journalist, writing for the newspaper
La Justicia Social in the early part of the 20th century, and later for the magazine
El Maestro and for
la Revista Musical with three articles published in 1940, 1941, 1944. to search for a national identify in the field of music. In 1929, the government decided to send three musicians, Roberto Cantillano, José Daniel Zúñiga and Julio Fonseca, to Guanacaste where they would compile, harmonize, and edit a compilation of folklore,
El Folleto de Música Folclórica Nacional. Three editions of the work were published in 1929, 1934, and 1935. ==Last years==