Mercury (Hg) heavy metal pollution is one of the serious problems that can threaten human health and ecosystems. In an effort to reduce mercury contamination, this research uses sea pandanus leaves (pandanus tectorius) as a natural biosorbent. The purpose of this study is to determine the contact time and adsorbing concentration capacity of sea pandanus leaves to mercury ions. One of the steps to reduce mercury contamination is by biosorption. The data obtained were analyzed using J.S.A.P software to determine the real difference test on contact time and adsorption concentration. The results of this study indicate that sea pandanus has a mercury adsorption capacity determined by the optimum contact time in the ratio of 1:100, the best optimum contact time is 60 minutes with an adsorption concentration of 100 ppm by achieving an adsorption of 0.372 mg/g using a mesh size of 120, Comparison of 1:75, the best optimum contact time is 30 minutes with an adsorption concentration of 0.907 mg/g using a mesh size of 120. Sea pandan leaves are proven as a potential biosorbent to remove mercury ions with the application of sea pandan leaves with seawater, which is 95% able to absorb heavy metals in polluted seawater.