<p>A new Underwater Vacuum Preloading Method (UVPM) is proposed to enhance the consolidation of marine clay below seawater level. The core concept of this technology involves anchoring large-diameter steel pipes into the marine clay alongside a sealing groove, creating a pumping system that overcomes the intake pressure loss limitations of conventional vacuum pumps. To evaluate its effectiveness, model tests were conducted to compare the consolidation behavior of marine clay treated with the proposed UVPM, conventional UVPM. The results demonstrate that the proposed UVPM significantly improves consolidation efficiency, yielding higher undrained strength and lower water content in the treated marine clay. The marine clay improved by the proposed UVPM reduced water content by 47% and increased undrained shear strength by 25.2% compared to those improved by the conventional UVPM. The undrained shear strength and water content obtained from conventional UVPM and the control setup without vacuum pumping were relatively close. This is because the proposed UVPM effectively transfer the hydraulic pressure as a pressure differential across the geomembrane to consolidate the marine clay.</p>