Mangroves play an important role in coastal community livelihoods of South Sulawesi. However, due to excessive and unsustainable use, mangroves experience degradation and deforestation in the past two decades. This study aims to detect mangrove extents, densities, and distributions changes during the periods 1997, 2007, and 2018 in Pannikiang Island, Barru Regency. We used three Landsat satellite imageries with acquisition 1997, 2007, and 2018 and implemented the multispectral classification and NDVI transformation methods, and the results were tested by ground truth. The results showed mangrove extents in 1997, 2007, and 2018 were 94.83 ha, 92.07 ha, and 91.64 ha, respectively. During these periods, mangroves decrease by 3.19 ha or an annual average of 0.15 ha. The decrease is caused by the expansion of settlements and aquaculture ponds. In 1997, the mangroves high-density class about 61.74 ha, moderate-density 14.19 ha, and low-density of 18.6 ha. In 2007, the high and low-density classes decreased to 54.53 ha and 12.29 ha, while the moderate-density increase to 25.35 ha. Finally, in 2018, the high-density class continues to decline by 43.36 ha, while for the low and moderate classes increases 15.34 ha and 32.67 ha, respectively, compared to the previous decade