The morphological characterisation of populations of exotic species is relevant for monitoring their impacts, as morphological traits are the first to react to environmental gradients. In Colombia, the giant African snail (Achatina fulica) has expanded across the country, occupying different habitats. We assessed the morphological variations of its shell in the cis- and trans-Andean regions of Colombia. We systematically and opportunistically collected snails at 12 locations in Colombia and applied geometric morphometric methods to analyse shell morphology variations. We found significant differences in A. fulica shell morphology, size, and allometry between cis- and trans-Andean regions. We also found differences in the frequencies of colour patterns, with pattern #2 being most frequent in the cis-Andean region and pattern #5 in the trans-Andean region. Results suggest that the shell morphology of A. fulica is an attribute that may respond to environmental, management or genetic differences between cis- and trans-Andean regions and that these differences should be considered in the design of management strategies across the country.