The purpose of this study was on understanding and interpreting five minoritised pre-service teachers' past educational experiences that impacted their first-time science microteaching experiences in a science teaching methods course. The study is unique because it illuminates and contributes to the literature on the importance of minoritised prospective teachers' educational experiences in their pre-service preparation and how these experiences challenge or contradict the urgency of equitable science instruction in traditional teacher education instructional discourse. The study draws on the literature on border crossing as a guiding theoretical framework, and phenomenology as a guiding methodological framework to analyse first time science teaching experiences. Data included videos and written narratives of first-time science teaching experiences. Analysis indicated that past educational experience of being left out in doing science underscored minoritised pre-service teachers' first-time science teaching experiences. Furthermore, they had created navigation strategies to counter the past educational experiences by challenging and modifying science teaching routines and devising equitable ways to use science teaching resources to cultivate a sense of belonging. The study suggests that future science education research would benefit from attention to minoritised pre-service teachers' experiences used to challenge or contradict past educational inequities.