In this note we prove that the solution of the stationary and the instationary Stokes equations subject to perfect slip boundary conditions on a 2D wedge domain admits optimal regularity in the L p -setting, in particular it is W 2,p in space. This improves known results in the literature to a large extend. For instance, in [21, Theorem 1.1 and Corollary 3] it is proved that the Laplace and the Stokes operator in the underlying setting have maximal regularity. In that result the range of p admitting W 2,p regularity, however, is restricted to the interval 1 < p < 1+δ for small δ > 0, depending on the opening angle of the wedge. This note gives a detailed answer to the question, whether the optimal Sobolev regularity extends to the full range 1 < p < ∞. We will show that for the Laplacian this does only hold on a suitable subspace, but, depending on the opening angle of the wedge domain, not for every p ∈ (1, ∞) on the entire L p -space. On the other hand, for the Stokes operator in the space of solenoidal fields L p σ we obtain optimal Sobolev regularity for the full range 1 < p < ∞ and for all opening angles less than π. Roughly speaking, this relies on the fact that an existing "bad" part of L p for the Laplacian is complemented to the space of solenoidal vector fields.