Many species of fish are capable of terrestrial locomotion. While these species often make use of specialized structures, many species can also perform effective terrestrial locomotion using the same set of locomotor tools (i.e. central pattern generators, musculoskeletal system, sensory systems) that are primarily adapted for an aquatic environment. Studies often look at locomotion in fully aquatic and fully terrestrial environments. However, this ignores the ecologically relevant transition between these environments and offers no opportunity to investigate whether terrestrial and aquatic locomotion in these species are distinct behaviours or a part of a continuum. Here, we test the hypothesis that the switch from swimming to walking is discrete in Polypterus senegalus by exposing fish to a series of environments spanning the aquatic-terrestrial transition. We report changes in kinematics, muscle activity and coordination of the two, focusing especially on environments in which environmental forces would shift from buoyancy-dominant to gravity-dominant. We show that while swimming and walking do appear to be distinct behaviours, P. senegalus use transitional behaviours in intermediate environments.