The intensity coherence function (ICF) of the acoustic wavefunction from a point source is derived by the path‐integral technique for transmission through internal waves in the presence of a sound channel. Separations in time are emphasized, although separations in transverse horizontal position, vertical position, and acoustic frequency are discussed. Approximate intensity coherence times, lengths, and bandwidths due to internal‐wave fluctuations are derived. Analytic approximations suitable for computer coding are presented for the micropath focusing parameter γ, which controls the deviation of higher intensity moments from the Rayleigh‐distribution values.