The internal structure of fiber reinforced geopolymer composite was investigated by microfocus X-ray computed tomography (µCT) under mechanical impact. µCT is a non-destructive, multi approach technique for assessing the internal structures of the impacted composites without compromising their integrity. The three dimensional (3D) representation was used to assess the impact damage of geopolymer composites reinforced with carbon, E-glass, and basalt fibers. The 3D representations of the damaged area with the visualization of the fiber rupture slices are presented in this article. The fiber pulls out, and rupture and matrix damage, which could clearly be observed, was studied on the impacted composites by examining slices of the damaged area from the center of the damage towards the edge of the composite. Quantitative analysis of the damaged area revealed that carbon fabric reinforced composites were much less affected by the impact than the E-glass and basalt reinforced composites. The penetration was clearly observed for the basalt based composites, confirming µCT as a useful technique for examining the different failure mechanisms for geopolymer composites. The durability of the carbon fiber reinforced composite showed better residual strength in comparison with the E-glass fiber one.