By considering the stochastic nature of microfluctuations in the real ocean, the conventional ray‐theory intensity relation is extended to permit consideration of partial coherence in multipath problems. The partial coherence factor is shown to be a function of the curvilinear range, the frequency, and the oceanographic conditions. In addition, a practical estimate for the standard deviation σIof the intensity about its expected value is found; σIis shown to depend on the partial coherence factor and to saturate as this factor approaches zero.