Lagoons are shallow coastal bodies of water separated from the ocean by a series of barrier islands which lie parallel to the shoreline. Sediment supplied to enclosed lagoons will influence the distribution and morphodynamics of coastal lagoons. Lagoons are re-shaped by erosion and deposition by the accumulation of material washed or blown over the enclosing barriers, and by the accretion of in-flowing river sediment. The purposes of this study is to describe the methodology and attain results for identification of multitemporal Landsat image data of the Segara Anakan Lagoon for the years 1978, 1994, 2003, and 2013. The method used in this study is a visual interpretation of Landsat by using GIS and remote sensing methods to produce maps of morphodynamics of a lagoon and multitemporal of a coastline change. The overall results for the identification of morphodynamics of coastal lagoons are the decrease of areas of water bodies, increase of areas of a land accretion, and coastline changes. The results are used to examine ecological management of coastal lagoons.