Research on preservice teachers' (PST) adaptive competence in physical education is critical to prepare them for effective teaching in an ever-changing pedagogical context. This study examined the adaptive competence of two PSTs (one male, one female) during their twelve-week school placement while teaching two 10th-grade classes. The adaptations to six core practices, namely: goals and assessment; establishment of rules and routines; management; content development; task presentation; and supervision and active monitoring were analyzed in 48 lesson plans. Twenty-seven adaptations were made by PST A (67.5%) and thirteen by PST B (32.5%). For both PSTs, the content development core practice had the highest number of adaptations (16), followed by management (10) and task presentation (5). No adaptations were made to rules and establishment of routines. While the invasion games showed the highest number of adaptations (N = 15; 37.5%), net-wall games had the highest number of adaptations per lesson. Most adaptations were made in volleyball. The type of physical education curriculum (distributed practice) imposed by the school, may have substantially impacted PSTs' ability to make adaptations to lesson plans. This study showed that PSTs put the most effort into adapting content development to the students they were teaching. Both PSTs had limited content knowledge in the teaching content, so future research should investigate the relation between PSTs' content knowledge and adaptive competence. In addition, interventions to improve PSTs' adaptive competence through reflection-on-action and expert supervision should be further explored.