Phonological processing of written characters has been recognized as a crucial element in acquiring literacy in any language, both native and foreign. This study aimed to assess Japanese primary school students' phoneme-grapheme recognition skills using both paper-based and touch-interface tests. Differences between the two test formats and the relationship between phoneme-grapheme recognition skills and interaction with digital tests were investigated. We hypothesized a relationship between paper test performance and digital item performance. Participants were sixth-grade students from two public schools. The results of comparison tests indicated that the touch-interface test had lower success rates compared to the paper-based test for most items, suggesting a difference in performance patterns. A consistent relationship between phoneme-grapheme knowledge tested on paper and successful digital interaction was found. Findings highlight the potential of touch-interface assessments for assessing phoneme-grapheme recognition skills in primary school classrooms and suggest incorporating more digital tasks to enhance student adaptation. [Note: The issue number (1) shown in the citation on the PDF is incorrect. The correct issue number is 2.]