 Between 1967 and 1977 Belen performed in multiple locations around the United States, Brazil, Portugal, and Spain.She sang for the Tucson Opera (now the Arizona Opera) and the San Francisco Opera.She sang the principal soprano role for "La Traviata", "Madame Butterfly", and "La Boheme", as well as performing in "La Sonnambula", "Daughter of the Regiment" (La fille du régiment), "The Magic Flute", and "The Abduction from the Seraglio".