Previous research on mentor training in early childhood education and care (ECEC) teacher education has shown that relationships are at the core of mentoring (Kupila et al., 2017; Ukkonen-Mikkola et al., 2021). This article presents findings from a qualitative study that aims to explore ECEC teachers’ relational professionalism (Furu & Sandvik, 2019) during mentor training. Our research material consisted of essays (n = 77) from the final reflective essay of a mentor training course for ECEC teachers, which were analysed through narrative analysis (Clandinin et al., 2016). The results show that ECEC teachers’ relational professionalism is built in three types of entangled relationships: (1) relation to oneself, (2) relation to the student and (3) relation to colleagues. The results imply that relationally professional mentors are a key factor that contributes to students continuing in the profession after graduation. This requires that the university engages in cooperation and relationships with the ECEC centres that receive students in the practicum. The university needs to offer mentor training and develop rich opportunities for mentors, their colleagues, and leaders in ECEC to establish relationships with all parties involved on all levels.