Human-induced land use and land cover changes significantly influence the Earth's surface temperature, especially in rapidly developing regions. This study investigates the impact of urban development associated with the Anzali Free Zone Organization, located along the southern coast of the Caspian Sea, on land surface temperature (LST) changes over a 24-year period (2000–2024). Multitemporal Landsat ETM+ and OLI satellite imagery were employed to analyze spatial and temporal variations in surface temperature. Following radiometric, atmospheric, and reflectance corrections, the Normalized Difference Vegetation Index (NDVI) was calculated to derive vegetation fraction (PV), which in turn was used to estimate surface emissivity. Brightness temperature was then computed using thermal bands, and LST was derived via the single-channel algorithm. The results indicate a significant alteration in LST, ranging from 16.5°C to 41.7°C in 2000 and from 20.1°C to 37.3°C in 2024. These temperature variations correlate strongly with reduced vegetation cover and the expansion of impervious surfaces driven by increased housing demand, trade, and tourism in the Free Zone. The findings demonstrate a clear manifestation of the Urban Heat Island (UHI) effect, underscoring the ecological consequences of unchecked urbanization. This study highlights the need for sustainable land use planning and vegetation conservation strategies to mitigate thermal stress and preserve environmental integrity in coastal urban areas.