Our study explored EFL writing skills in relation to self-experience in an authentic learning context with the help of a mobile application. Two authentic writing activities ('Tell your story' and 'Describe your context') were designed and compared to see if they resulted in significant differences in EFL writing performance and writing behavior. The results showed that the experimental group who completed the "tell your story" exercise exhibited significantly better writing performance than the control group who completed the "describe your context" exercise'. More specifically, the experimental group used more vivid words and vocabulary to write about their surrounding contexts than the control group. Our observation and study results showed that using authentic materials in storytelling exercises motivate students to share their experiences, which not only improves students' general EFL writing skills but also enhances their confidence to use English in real situations.