Two approaches to description of lidar returns at sensing seawaters with the allowance for multiple scattering in the small-angle approximation are considered. The first approach uses an analytical relation between signal components formed due to single and multiple scattering. The second approach is based on the additive property of the signal as a function of the solid reception angle and its asymptotic properties at a large reception field of view. The lidar return characteristics describing the effect of multiple scattering are calculated with the allowance made for microphysical properties of suspended matter in seawaters. A polydisperse suspension was modeled by two fractions of particles: fine fraction of mineral origin and coarse fraction of organic origin. The results presented could be useful for planning experiments on seawater sensing in order to increase the efficiency of inverse problem solution.