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Foundations of offshore marine structures are subject to cyclic forces that are caused by wind, water waves, and swells. It is thus important to utilize soil damping to optimize their design, related to dynamic amplification near the system resonant frequencies. Here, we investigate the damping properties of a soil element subject to combined nonzero average and cyclic shear stresses in cyclic direct simple shear (DSS) laboratory tests. Analysis of a limited number of clay specimens shows that the damping factor of the soil increases if a nonzero average load is superposed to the cyclic load. Under such loading conditions, the average strain will increase from cycle to cycle. A new rheological model justifies that the damping is increased when a static load is added to the cyclic one. Moreover, results from laboratory DSS tests on dense sand display a much stronger effect of the number of load cycles than predicted by commonly used parametric expressions from the literature. This is caused by a strong dilatancy of the dense sand. The analysis herein indicates that, for some soils and under certain loading conditions, the damping factor may behave differently than previously thought. In the case of combined static and cyclic loading, the increased damping may potentially be exploited in more cost-effective design of offshore marine structures.