This study examines and explores PSTs' fears realised during the practicum period. In order to achieve an in-depth understanding, a phenomenological and holistic approach has been adopted. Data were collected from 22 preservice teachers via reports with open-ended questions on a weekly basis during the whole practicum period. 211 reports were analysed through inductive thematic coding. The analysis led to discrimination of twelve different yet interrelated sources of fear. It is argued that PSTs' fears are learnt and resulted from a perception of threat, uncertainties involved in situations, possibility of deteriorating conditions of the future events and/or anticipatory reflections. The paper also explicates on the protective feature of fear, which is discussed to have a potential to support PSTs' self-development and professional-preparation.