The primary environmental features of the island in the Hooghly estuary include macro tidal activity, storms, wind, cyclonic waves, some sorts of sediment composition, and seasonal variations in the freshwater discharge. The primary objective of this study is to analyze the changes in the coastline between 1990 and 2024, utilizing remote sensing and GIS data. It was observed that the shoreline shifted towards the North East, North West, and Southern directions in the past 34 years in Ghoramara and the formation of new tidal flats named Basit Island in the year 2008 (approx.). Ghoramara Island is a protected tidal flat, whereas Basit Island is open tidal flats and relatively new and well-preserved natural tidal flats at Hooghly estuary. The study examined coastal areas from 1990 to 2024 using multitemporal satellite data, Google Earth high-resolution data, erosion and accretion rates of the oldest and youngest shorelines, and Shoreline change analysis of Ghoramara and Basit Island. Field survey data were used to validate the changes. At Ghoramara Island, the total area was reduced from 8.145 km2 in 1990 to 3.59 km2 in 2024. On the contrary, in the case of Basit Island, the changes in the total area significantly increased from 1.161 km2 in 2008 to 6.924 km2 in 2024. The study identifies shoreline changes as the after-effect of erosion-accretion over time.