| 1961 | Assistant Professor for André Gerter at the Royal Conservatory of Music in Brussels until 1970. | |
| 1970 | Appointed, by merit competition, Official Professor of Violin at the Royal Conservatory of Music in Brussels. | |
| 1970 | Guest professor to the First International Course of Music “Manuel de Falla”, under the Festival of Music and Dance of Granada. Position held until 1984. | |
| 1971 | Professor of violin for the International University Courses “Música en Compostela”. Position he continues to hold and was named Director in 2011. | |
| 1977 | Profesor Extraordinario de la Chapelle Musicale Reine Elisabeth, Bélgica, durante 9 años. | |
| 1979 | Courses given at the Joaquín Turina Hall, Royal Theater of Madrid, at the request of the Comisaría General de Música. | |
| 1983 | Starting in this year, he has given courses at the High Conservatory of Music in Tenerife. | |
| 1983 | Professor of violin for the JONDE (National Youth Orchestra of Spain) from the time of its founding. | |
| 1986 | Professor of the High Municipal Conservatory of Music of Barcelona. | |
| 2000 | Professor of ESMUC (Higher School of Music of Cataluña). | |
| 2001 | Professor of the High Conservatory of Music of the Balearic Islands. | |
| Anexo | Como testimonio de la labor docente desarrollada por León Ara a lo largo de más de 40 años están los numerosos alumnos suyos que ejercen como profesores en centros de enseñanza superior de música tanto en Bélgica como en España. Así como otros muchos que están presentes en casi todas las grandes orquestas belgas y españolas. |