The study analyses the competencies of trainee teachers in solving mathematical modelling problems, characterising levels of achievement, interrelationships and their influence on success, using GeoGebra and peer collaboration. It examines errors and difficulties in each competency. The results show lower development in coding, validation and interpretation of results, and a significant correlation between representation, visualisation and construction of real models. Although the impact of GeoGebra and collaboration was not measured, these elements were observed to be promising for inquiry, visualisation and validation in mathematical modelling.