Observations of seismic anisotropy are a powerful tool to explore deformation and flow in the deep mantle. Recent work has explored how flow in the deepest mantle interacts with major structures such as subducting slab remnants, large low velocity provinces (LLVPs), and mantle plumes. However, a comprehensive framework describing the patterns and drivers of flow in the mantle’s bottom boundary layer is only starting to emerge. Here we target the lowermost mantle beneath Australia and the surrounding region, which encompasses slab remnants, the edge of the Pacific LLVP, and a previously identified possible mantle plume that has not yet reached the surface. We apply a recently developed approach that relies on array processing of SmKS phases, which increases signal-to-noise ratios and enables analysis of low-amplitude phases such as S3KS. We supplement our differential SmKS splitting measurements with analyses of ScS phases that sample our study area. We infer strong seismic anisotropy in localized regions, including along the southwestern edge of the Pacific LLVP and in a region south of Australia that is dominated by high seismic velocities. To provide an interpretive framework for our observations, we compare them with the results of instantaneous mantle flow models and with whole-mantle S wave tomography models. Our results support an emerging view of lowermost mantle dynamics that involves slab-driven flow, interactions between mantle flow and structures such as LLVPs, and strong deformation at the root of mantle plumes, including a plume that has not yet reached the surface.