This case study investigated how three teachers developed mathematical modelling activities integrated with content standards through participation in a course on mathematical modelling. The class activities involved experiencing a mathematical modelling activity, reading and rating example mathematical modelling activities, reading articles about mathematical modelling activities, and in-class discussion and feedback. We describe the teachers' development process and how well structured the activities were based on six principles of mathematical modelling activities. We also describe the teachers' interpretations of the six principles connected to their modelling activity. Two of the teachers were able to develop modelling activities that met the six principles while one teacher did not meet the generalizability and self-assessment principles. Developing mathematical modelling activities is a difficult task and the class activities allowed the teachers to go through revisions with their mathematical modelling activities to allow the opportunity for the activities to be properly structured.