Estimation of the bearing of a farfield signal source with a small‐diameter circular array of hydrophones is studied in this paper. It is shown that for isotropic farfield noise the Cramér–Rao bound can be simply evaluated via a spatial harmonic representation of the array response. Use of the derived expression for practical bearing estimators employing superdirectivity is justified by showing the equivalence between the maximum‐likelihood estimate and one obtained by the formation of superdirective beams. An expression for the average bias resulting from anisotropy of the ambient‐noise field is also derived using a spatial harmonic representation.