The research on geopolymer concrete (GPC) using sea sand in the world has been carried out over 10 years. In Vietnam, the studies on the GPC with sea sand are shortage. Also, the potential of the the GPC with sea sand in coastal infrastructure construction has not been significantly considered. In this paper, to initially evaluate the ability the sand taken from Cua Lo coast, Nghe An province, Vietnam to manufacture GPC without any futher treatment, an experiment design method we carried out in our university laboratoty. The result outcome has successfully proposed 03 GPC mixtures with the graded factor of 15, 25, and 35 MPa, respectively. The achievement of the study suggested that it is possible to replace conventional coarse sand by sea sand in the production of GPC. Thus, our study will in turn contribute to the efficient use of sea sand resources, reducing exploitation of amount of depleted traditional coarse sand.