The mechanics of suspended sediment under wave action are investigated. The results apply to regions well beyond the surf zone where the flow field, though irregular in appearance, is still amenable to mathematical expressions in gross terms. The motion of the suspended sediment particle and that of the fluid particle in a wave field are found to have an amplitude difference and a phase lag. The suspended sediment concentration is a hyperbolic trigonometric function of water depth. The relation reduces to a power law for shallow water cases. The value of power is found to be a function of particle settling velocity, fluid particle velocity, and wave number. Wave mass transport velocity is derived on the basis of turbulent boundary layer as the lower boundary condition. Finally, it is found that the rate of suspended sediment transport in a wind-generated random wave field can be approximated by a power function in terms of wind velocity.