Creeping flow around a solid sphere is solved numerically using two regularized constitutive equations that approximate a Bingham material. The yield surface cannot be easily established from contours of the yield stress obtained with finite values of the regularization parameter due to numerical constraints. The outer yield surface can be estimated from the values of the normalized second invariant of the deformation rate that are invariant with respect to the regularization parameter, and the limiting solution for creeping flow of a Bingham material about a rigid sphere appears to be achieved.