Workplace-based experiences are considered centrally relevant in the professional preparation of prospective teachers. In spite of this, few studies have focused on the assessment of workplace-based learning (WBL) in early childhood education (ECE). This study aims to examine pathways of professional learning of students attending an ECE professional Master programme in Portugal, based on an authentic and participatory approach to assessment. A cohort of 62 students participated in this exploratory study. Data were collected through an assessment grid organised in four domains (observation, planning, action and reflection) and 25 dimensions, in two moments: interim regulatory assessment and final assessment. Key findings point to statistically significant differences between the two moments, showing the progress of students at the level of competences in all domains and dimensions. Results allow to identify tendencies on students' learning pathways in core domains of professionalism and represent an input for understanding the effectiveness of the ECE professional Master programme.