Self-regulated learning (SRL) processes are used frequently by elite athletes and are important for optimizing practice efforts during talent development (McCardle et al., 2017). Before someone becomes self-regulated, they are co-regulated by a more experienced other, e.g., a coach (Glaser, 1996). Scaffolding, a form of co-regulation, has three conceptual characteristics: contingency control; fading; transfer of responsibility (van de Pol & Elbers, 2010). While popular in education, no studies have assessed scaffolding in sport. We explored scaffolding in a naturalistic, instrumental case study with an experienced female coach (aged 53, national level) and her competitive male figure skater (aged 15, provincial level) using a) participant observation, field notes, and recording and analysis of dialogue at 16 practices, and b) three separate interviews with the coach and skater at early-, mid-, and late-season. Data were thematically analyzed (Braun & Clarke, 2006). Deductive interpretations, guided by scaffolding characteristics, proved difficult due to overlap of conceptual constructs. Inductive analysis revealed complex, sport-specific nuances. Co-regulation occurred at both micro- and macro-levels. Micro-level co-regulation was illustrated by a "co-regulatory interface" – a pivotal interaction zone described by contributing roles and expectations for each actor, shared roles, and embodied transitory process related to the skater's SRL. A mature, enriched interface was predicated on prerequisite conditions for coach and athlete. Fading differed from education because of non-linear aspects when the coach would return to refine an element if it was incorrect. Findings suggest scaffolding manifests in sport, with self-regulation married to co-regulation, and more specifically, the interface.