This case study discusses an online second language teacher education course, designed for teachers, teacher educators, directors of studies and course designers, created and run by the authors, who are both members of a language services cooperative in Barcelona. Information about the cooperative is given, and the events leading to the start of the project are described. Having outlined Long’s (2015) approach to task-based language teaching (TBLT), which serves as the model for the course, we describe the course itself, and the components of its twelve sessions. We go on to explain how we wrote the course and how, once complete, it was marketed. The first implementation of the course is then described, including details of the participants’ working roles; their highest qualifications; their engagement with course activities; the completion rates; and feedback. We then explain how the second implementation reflected changes we made to the course as a result of our reflections and feedback. Finally, we discuss the strengths and weaknesses of the course, paying particular attention to loop input (Woodward, 2003) and to the principle of faithfully reflecting TBLT processes so that the course practices what it preaches.