Current studies have reported that secondary students are highly engaged while playing mobile augmented reality (AR) learning games. Some researchers have posited that players' engagement may indicate a flow experience, but no research results have confirmed this hypothesis with vision‐based AR learning games. This study investigated factors related to students' engagement – as characterized by flow theory – during a collaborative AR, forensic science mystery game using mobile devices. School Scene Investigators: The Case of the Stolen Score Sheets is a vision‐based AR game played inside the school environment with Quick Response codes. A mixed methods approach was employed with 68 urban middle school students. Data sources included pre‐ and post‐surveys, field observations and group interviews. Results showed that neither gender nor interest in science was an important predictor of variability in flow experience. Gaming attitude uniquely predicted 23% of the variance in flow experience. Student flow experience features included a flash of intensity, a sense of discovery and the desire for higher performance. The findings demonstrated a potential for mobile AR science games to increase science interest and help students learn collaboration skills. Implications for future research concerning mobile AR science games are discussed.