The Mekong River,one of the largest rivers in Asia,used to discharge annually 160 million tons(Mt)to the sea,with a historical long-term rapid seaward delta growth rate(16-26 m/yr),and resulted in forming a worlds third largest delta in the western South China Sea.New shoreline analyses of 43-yr high-resolution satellite images(1973-2015)using ArcGIS tools indicate that the growth rate around the current Mekong river distributary mouths(from My Tho southward to Bassac)in the east(Zone-1)had been steadily decreasing from 8.66 m/yr in 1970s to 4.5 m/yr during 2005-2015,the area accretion decreasing from~2 to 1.15 km2/yr.