Providing well-trained teachers is a crucial factor for enhancing educational quality. Nowadays, nearly half of Spanish teachers feel that the content and teaching practices learned during their initial teacher education are not applicable in school settings. This indicates a gap between theory and practice which must be bridged by re-thinking initial teacher education. Moreover, we consider that improving initial teacher education demands listening to teachers’ voices. Nevertheless, little is known about their voices regarding an effective initial teacher education. This research aims to develop the teaching of informational literacy by drawing partially on teachers' voices. Informational literacy is defined as the capacity to search, treat, and communicate information. We interviewed thirty teachers to explore their voices concerning the required knowledge for teaching informational literacy. A deductive-inductive content analysis of these interviews was performed using the Technological Pedagogical Content Knowledge (TPACK) framework. Preliminary findings show that, according to teachers, student-teachers need to learn about: Pedagogical Knowledge, Technological Knowledge, Content Knowledge, Technological Pedagogical Knowledge, Pedagogical Content Knowledge, Technological Content Knowledge, Contextual Knowledge, and Professional Knowledge. Participants highlighted the teaching of Technological Knowledge and Technological Pedagogical Knowledge during initial teacher education. In addition, teachers were classified into three groups depending on the knowledge they emphasized: (1) Technological Knowledge, (2) Pedagogical and Contextual Knowledge, and (3) Pedagogical and Content Knowledge. To conclude, our research provides valuable insights for designing learning opportunities within initial teacher education focused on developing student-teacher competence in teaching informational literacy. Results are relevant for teacher educators who want to innovate in initial teacher education. Specifically, by integrating theory and practice through the incorporation of teachers' voices.