We still have a considerable lack of understanding about the constituents of our Universe, and tensions are starting to arise between datasets as we reach subpercent precision constraints.  In this talk, I will mention how we can use gravitational waves as a new independent tool to learn about cosmology. I will discuss how we can set constraints on the current expansion rate of the Universe, H0, as well as test the nature of dark energy with the observation of binary neutron star mergers.