We study cohomological obstructions to extending group actions on the boundary ∂M of a 3-manifold to a C 0 -action on M when ∂M is diffeomorphic to a torus or a sphere. In particular, we show that for a 3-manifold M with torus boundary which is not diffeomorphic to a solid torus, the torus action on the boundary does not extend to a C 0 -action on M . Moreover, we use techniques from 3-manifold topology, homotopy theory, and low-dimensional dynamics to find group actions on a torus and a sphere that are not nullbordant.