Developing a professional identity is a key element of the transition into the teaching profession. Limited research exists on professional development activities and ideas that support beginning teachers' development of their professional identity in practice. For this study teachers participated in an induction programme that focused on beginning teachers' professional identity. This study reports on the development and testing of three online professional identity assignments with 46 beginning teachers from 11 secondary schools. These assignments were based on research findings regarding the influence of 'significant others' and 'stories to live by' on teachers' professional identity development. Analysis of the results reveals that the assignments each provide valuable input for doing identity work with beginning teachers in view of their further professional development. It can be concluded that the assignments we developed are useful for beginning teachers to reflect on and make sense of who they are and want to become.