Southwest Australia is a biodiversity and endemism hotspot for herpetofauna. Three unusual Australo-Papuan myobatrachid species occur in sandy habitats across semi-arid and arid regions in the Southwest corner, and differ from most other burrowing frogs by burrowing head-first in a forward direction, a behaviour which appears to have resulted in extreme morphological adaptations. Interestingly, the degree of morphological adaptations and fossoriality varies among them, but they are all starkly different from their non-burrowing sister species. Using diffusible iodine-based contrast-enhanced Computed Tomography (diceCT) we were able to extract data of both bones and soft tissue of forward burrowers and non-burrowers to assess morphological adaptation to burrowing across a fossoriality gradient. We used 3D geometric morphometric analyses to identify morphological integration patterns among fore-limb bones. We also assessed 3D muscle architecture associated with forward burrowing behavior. Finally, using Finite Element Analyses we assessed the biomechanical properties of the humerus and radioulna. We discuss their morphological evolution, biomechanics, and soft tissue differences in the context of different soil properties and paleoclimatic events that might have contributed to the morphological adaptations for a fossorial lifestyle in this clade of bizarre frogs. We hypothesize that our results could help to infer behavioural and ecological habits of extinct taxa.