The consequences and affordances of online teacher education remain understudied, even as it promises greater accessibility. The COVID-19-related pivot to emergency remote teaching offered a novel opportunity to study how practice-based teacher educators transitioned courses online. This multiple case study of six graduate student instructors examines the effects of transition on four pedagogies of practice-based teacher education. We discovered that 1) representations and 2) approximations of practice could be adapted with minimal disruption. However, 3) enactments could be transitioned only with loss and cascading effects that impacted 4) reflections on practice. These findings can promote teacher educators' awareness of how to create intentionally designed online practice-based teacher education courses. [For the corresponding grantee submission, see ED621536.]