A thick layer of sand with high groundwater levels, and highly variable fines content ranging from 0.25% to 85% is the characteristic of the soil layer in Babarsari, Sleman, Special Region of Yogyakarta. Being a seismic-prone area, Yogyakarta city requires safety measures against liquefaction, as it often leads to severe damage or failure of infrastructure such as buildings, bridges, and others. Sand containing fines exhibits higher liquefaction resistance compared to clean sand at the same Standard Penetration Test (SPT) value. The liquefaction resistance tends to increase as the amount of fines increases. In this study, sand-containing fines are assessed to evaluate their effect on (N1)60CS and liquefaction resistance. Safety factors for liquefaction are also assessed, incorporating Standard Penetration Test (SPT) data from the local area of Babarsari Yogyakarta. The effect of fine content (FC) ranging from 5 to 45%, on a safety factor of liquefaction is further analyzed. The results of this research show that an increase of fines content up to ± 35% with (N1)60CS >  ± 16% enhances soil liquefaction resistance, Cyclic Resistance Ratio (CRR), increases Safety Factor (SF), and reduces Cyclic Stress Ratio (CSR) due to earthquakes.