The purpose of this study was to examine the effects of a tactical games model instructional plan on game-play volleyball performances of elementary school students, taking into account their skill level. In total, 39 fourth-grade students (average age: 8.9 years) participated in a 13-week unit, in which each lesson exaggerated the use of small-sided games. In-game performances were assessed via the Team Sport Assessment Procedure, while students played a 10-minute modified game (four versus four). Data were collected pre- and post-intervention, and after the summer vacation (retention test). A 2 (skill level) × 3 (time) analysis of variance with repeated measures was used to compare students' performance, and the relevant effects were interpreted mainly by means of confidence intervals and effect size measures. At the end of the instructional period, all participants had an overall moderate to large improvement, and this global improvement seems to have remained at least until the end of the summer vacation. Lower-skilled students attained a larger and more established improvement than high-skilled students did. However, some detrimental effects on in-game students' performance existed at the end of the instructional period. Therefore, teachers have to take into account students' skill levels when designing their lessons because, if small-sided games are adequately considered and managed, students' learning processes can be enhanced. Furthermore, the students should be assigned appropriate learning activities to avoid summer learning loss in physical education.