This study examines land use changes and carbon sequestration in Wattana district, Bangkok, Thailand, over the past 20 years. Utilizing detailed satellite imagery analysis, the research reveals trends in above-ground carbon storage in the area. From 2001 to 2021, significant shifts in vegetation cover and carbon sequestration dynamics were noted. Initially, in 2001, sparse vegetation predominated, covering 47.53% of the district, with very limited moderately dense vegetation (0.35%) and no areas of high vegetation density, indicating low biomass. Over half the district (52.12%) was used for residential purposes, water bodies, and other land uses. By 2021, the district underwent substantial changes: high-density vegetation areas remained small (0.02 km2), but moderately dense vegetation expanded to 0.92 km2 and sparse vegetation spanned 6.44 km2, making up 7.04 and 49.56% of the area, respectively. These changes suggest a richer and healthier urban ecosystem, highlighting the role of strategic urban planning in enhancing green spaces. Moreover, biomass analysis using the above-ground carbon sequestration (AGCS) equation showed a significant increase in carbon sequestration potential. In 2001, the AGCS was 22,440.89 tons, or 1726.40 tons/km2. By 2021, it rose to 37,742.62 tons, or 2935.78 tons/km2, marking a 70.05% increase and indicating a greater capacity for carbon capture in Wattana district over the two decades.