The number of students enrolled in online courses is increasing steadily. Distance education offers many advantages, but also has inherent challenges. Successful distance education needs a thoughtfully designed instructional strategy where students are supported to actively create knowledge. We present the design and evaluation of three online-based courses in health informatics. The courses were based on a collaborative instructional strategy. The evaluation comprised workload analysis, student evaluation, student interviews and student reflections. Students expressed high satisfaction with online learning, despite a high workload, and high perceived learning outcomes. Using the Community of Inquiry framework as reference, we found very high levels of teaching presence, social presence and cognitive presence. Summarizing, we found that the chosen instructional strategy supported student-centered, collaborative learning. We conclude by presenting lesson learned for online-based instructional design.