Farming in offshore waters to address the increasing demand for food fish is as much a technologicalchallenge as a social challenge. At present, there are only few successful cage design concepts for off-shore conditions. In a series of recent works by the authors, the single-point mooring (SPM) cage concepthas been identified as being potentially suitable for mariculture in offshore waters. In contrast to cageswith manual or automatic control of the submergence, the feasibility of the self-submersible SPM cagedepends on its “empirical” operational performance in offshore environments. This paper examines thesubmergence characteristics of the cage concept in random waves with following current using numericalsimulations and experimental model tests. The scaled model tests confirmed the submergence charac-teristics of the cage system that were observed in the numerical simulations. In random waves, the cagesystem responded to increasing wave regimes with additional submergence. However, the level of sub-mergence was found to be less pronounced than the cage submergence response in regular waves, whichwas investigated as part of earlier studies. While the cage system with less reserve buoyancy submergeddeeper, the peak factor of the wave spectrum did not substantially change the submergence characteris-tics. It was also found that the cage system is dynamically stable during and after submergence, regardlessof the magnitude of the wave heights observed in random seas.