In the field of child-robot interaction, social robots promote motivational learning across diverse educational contexts. This study explored primary school pupils’ learning experiences, perceptions, and interactions in physical education activities facilitated by three social robot instructors. We employed human-centered and persuasive design approaches to co-design robot-assisted activities with two physical education professionals. These activities were qualitatively evaluated with 22 pupils aged 12 to 13 years within a 2-hour summer camp. Despite most pupils having minimal prior robotic experiences, they reported positive learning outcomes by showing an improved understanding of physical education concepts and robot literacy. Our study highlights that physically embodied robots benefit physical education, as their multimodal features and physical presence effectively sustain pupils’ motivation and engagement. We conclude with four design implications for integrating social robots as motivational instructors in children’s physical education.