For too long the aromatic aza-Claisen rearrangement has been the poor relation of its oxygen counterpart. We demonstrate that on-water catalysis facilitates the rearrangement of reverse N-prenylated naphthylamines and anilines, and transforms the aromatic aza-Claisen rearrangement into a synthetically viable reaction. We use this reaction to probe the mechanism of on-water catalysis, and provide compelling support for the acid-catalysis hypothesis.