We discuss a course on mathematical modelling designed and implemented in a Master's Programme for in-service mathematics teachers using an online modality. Participants are in-service Mexican and Latin American high school and university mathematics teachers. The course adopts the SRP-TE methodology proposed by Ruíz-Olarría (2015) and satisfies the principles of online participation suggested by Scott (2010). Our goal is to provide teachers with tools for creating, adapting and managing mathematical modelling activities based on the epistemological, didactic and ecological analysis proposed by the Anthropological Theory of the Didactic.