This study portrays the qualitative potential of three iterative reflective problem posing instructions for preservice teachers to elicit the characteristics of mathematical modelling problems. The instructions are characterised by a problem posing prompt and different forms of reflective practices, reflection-on-action, reflection-in-action, and reflection on reflection-in-action. Each instruction was administered to a distinct cohort of 24 preservice mathematics teachers who worked in pairs to pose a modelling problem and provided a written reflection. A total of 36 modelling problems and associated reflections were analysed through content and thematic analysis. While content analysis was held separately for each instruction to elicit the task characteristics, thematic analysis compared these three sets of content analysis to reveal patterns that denote the potential role of the different forms of reflection for incorporating the task characteristics into modelling problems. The findings indicated an aptitude for the context to be a medium for developing mathematical insight, relying on the context-content balance and open-endedness nature of the modelling problems. Furthermore, preservice teachers' reflective articulation addressed the sources of openness (i.e., multiplicity of solution methods, acceptable answers, assumptions, and realistic considerations) and ways operating with the open-ended nature of the modelling problems. Hence, reflective problem posing instructions demonstrated a form of educational support for posing modelling problems, the implications of which are further discussed.