Integrating socioscientific issues (SSI) into classrooms to address science-related social matters has gained attention. Educational comics show promise in introducing SSI content; however, previous studies focus on higher education, leaving gaps in elementary school implementation. We interviewed eight practitioners to explore design principles for SSI-based educational comics for elementary students. Key aspects included content considerations (storyline, SSI complexity, cross-disciplinary perspective, and discussion) and visual design elements (coloring, comic elements, character consistency, and infographic use). Utilizing these insights, we designed a comic prototype, which we present in this study. The findings contribute to understanding crucial design elements for future comic trials and serve as a valuable resource for designing age-appropriate comics for elementary school students.