The existence of groynes can affect the morphology of seashore. Groynes are structures that are mainly built to prevent erosion and enable sediment transport forming accretion on the shore. In the long term, erosion and sediment transport will cause a change in coastline. This paper aims to observe how the coastline will change due to the installment of a groyne on the shore. The coastline curves were simulated by using mathematical modeling. The coastline change equation which was derived from the continuity equation was solved by using the Laplace transform. The results indicate that erosion takes place on the downdrift side of the groyne while accretion takes place on the updrift side. The magnitudes of erosion and accretion increase over time. The increase rates was observed by applying variation to the value of the parameter such as breaking wave speed.