Online learning is being implemented due to the emergence of the COVID-19 pandemic. This is based on the reduction of cases and casualties to the danger and severity of the disease. Though several compliments were encountered in the implementation of this educational process, English instructors at secondary and tertiary levels continue to protest the change. To respond to this dilemma, the development of blended learning (a combination of online and offline learning) emerged. Therefore, this study was intended to develop task-based blended learning for English correspondence education and to identify and explain the learning aspects in the model development. Approximately 120 students from four classes of semester 6 were selected and divided into two groups (experiment and control groups) since a research and development model was used for analysis (Dick & Carey, 1990). The draft model was further validated and piloted for several meetings. The results show effective learning materials containing five sections, namely (1) activity lead, (2) mind mapping, (3) refocusing, (4) writing, and (5) reinforcement. The materials were designed through the provision of tasks in every section, therefore integrating the students’ use of four language skills. In addition, these materials were designed according to lesson plan, learning syntax, and assessment tools.