This study investigated teachers' classroom practices in teaching English writing skills through competence-based language teaching among secondary students in the Mtama district. It aimed to identify teachers' instructional strategies and explore the challenges faced in ordinary-level classrooms. Employing a qualitative case study design, the research involved 32 participants and collected data through classroom observations, interviews, and focus group discussions. Data were analysed through thematic analysis. The findings revealed that teachers employed various instructional strategies, including dictation, demonstrations, question-and-answer sessions, discussions, and oral presentations. However, several challenges hindered the effectiveness of teaching English writing skills, such as insufficient teaching materials, unpreparedness among teachers, students' poor English background, inadequate time for writing practice, and lack of commitment. The study concludes that these obstacles significantly affect students' ability to achieve writing skills. It recommends the use of communicative instructional strategies to ensure active student engagement and the provision of sufficient textbooks in secondary schools.