Using a holistic biliteracies framework, this longitudinal comparative case study explores how two racioinguistically marginalized BPSTs (one heritage Spanish/English bilingual and one initially Spanish-dominant Mexican national) grew in their understanding of biliteracies development and their enactment of biliteracies pedagogies in the beginning of their career. Findings suggest that both BPSTs found intentional space to develop Spanish literacies, implementing strategies across language domains and modalities, and bilingual identities en convivencia to primarily influence biliteracies development. Of those pedagogies they enacted, the two BPSTs demonstrate regular use of two of the four characteristics of holistic biliteracies pedagogy: an interactive approach and development of oracy, reading, and writing with an emerging spirit of convivencia. Implications for BPST education research and practice follow.