The Ring of Fire traverses Japan, and many earthquakes occur there. Pumice sand is one of the materials often found in volcanic areas. Due to the swift cooling process, it is very porous, making it susceptible to crushing. When an earthquake occurs, pumice sand also has liquefaction potential and often triggers landslides in several areas. This research aims to determine pumice sand's liquefaction potential to provide a design reference. This study used unnatural pumice sand from Kyushu Island's Kirishima mountain area, sold by agriculture companies. Initial attributes were studied, including relative density (D_r) and specific gravity (G_s). Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) testing were used to establish pumice sand's pore character and chemical composition. Pumice sand was remolded, and various undrained triaxial cycle tests were performed with cyclic stress ratios (CSR) of 0.15, 0.20, 0.25, 0.30, and 0.35 and D_r fluctuations between 40% and 70% and also a variation of confining pressure 50 kPa and 100 kPa. The outcomes of this study demonstrate that a higher density of pumice sand leads to a more significant number of cycles required to attain liquefaction conditions. At the same time, confining pressure significantly affects liquefaction resistance, which can be seen as a reduction in confining pressure also increases liquefaction resistance.