This study explores how French-secondary-trainee teachers perceive their professional development over their year-long training. Two research questions are addressed: How prominent is workplace learning in teaching competencies acquisition? Is there a relationship between learning modes and the kind of teaching competencies to be acquired? Four hundred and seventy-three secondary-trainee teachers were asked to complete a questionnaire in which they rated to what extent 28 teaching competencies were being acquired at the end of the one-year training, along with the learning mode of these competencies. The findings suggest that learning on workplace is a multifaceted process that cannot be curtailed to mentoring.