This study describes the practicum-mentors' identity in a teacher education context based on Dialogical Self Theory (DST) and the related 'position' and 'I-position' concepts. Participants were 48 Spanish and Canadian primary and secondary teachers who participated via an online written survey. The data were analysed using qualitative and quantitative procedures. Findings show a comprehensive description of nine types of positions and twenty types of I-positions. Based on these categories, three clusters of practicum-mentors, which represent three different ways of being a mentor, were identified: (1) a collaborative partner focused on student-teacher (ST) professional development, including the design, and teaching of ST skills acquisition; (2) a collaborative partner focused on design, teaching, and assessment of ST skills acquisition, and (3) a coaching partner focused on teaching and individualised ST learning. The findings can promote closer collaboration between universities and schools concerning the design of more relevant professional development for mentors based on the three identified ways of being a mentor.