The purpose of this study was to investigate the long-term effectiveness of a three-dimensional (3D) computer modeling supported predict–observe–explain (POE) strategy on pre-service science teachers' understanding of lunar concepts. Thirty-three preservice teachers participated in the study. A questionnaire was used to assess participants' understanding of the phases of the Moon and eclipses before, after, and 22 months after the instruction. Semi-structured interviews were conducted with six participants before and after the instruction. The results demonstrated that few participants had a scientific understanding about the targeted lunar concepts before the instruction. However, the majority of the participants had a scientific understanding after the instruction indicating that the instructional intervention was quite effective in facilitating conceptual change. The results also demonstrated that twenty-two months after the instruction most participants maintained their scientific conceptual understanding suggesting that the powerful learning environment designed for this study was effective in promoting a durable conceptual change.