This study investigates the challenges that L1 Arabic EAP students experience in creating coherent texts, specifically concerning the use of the systemic functional linguistics (SFL) notion of Theme. Data included twenty-two writing samples of eleven students throughout a year-long academic writing course. The texts were analyzed for marked Themes, Thematic progression (TP), and multiple Themes. Results show that marked Themes increased significantly, not only facilitating the reading of the texts but also pointing towards possible development in reader awareness. Additionally, the use of coherent TP patterns improved slightly, indicating better choices in building on and developing meanings. In contrast, the use of multiple Themes did not increase, demonstrating a lack of sophistication in orienting the reader. It can be concluded that writing instruction to L1 Arab speakers should ensure that all three Thematic features examined in this study are made visible and practiced.