Seagrass is a coastal ecosystem that plays a role in absorbing CO₂ and mitigating climate change. At Bandengan Beach in Jepara Regency, there has been no time-series monitoring of seagrass changes for the past 19 years, creating a data gap. This study aimed to assess the ability of seagrass to absorb CO₂ and store organic carbon (Corg) as well as to examine the temporal changes in seagrass beds at Bandengan Beach from 2001 to 2020. A combination of remote sensing and field survey methods was used in this research. Carbon content was calculated using the Loss On Ignition (LOI) method, while seagrass cover and biomass mapping were analyzed using the Lyzenga and supervized classification methods. Three seagrass species were identified: Cymodocea serrulata, Thalassia hemprichii, and Enhalus acaroides. The seagrass area decreased by 1.4 ha (68%), from 2.05 ha in 2001 to 0.64 ha in 2020. The highest density (663 individuals per m²) and the highest biomass (481.28 g DW per m²) were dominated by C. serrulata, which also exhibited the highest carbon stock potential: 16.42 gC per m² above ground (AGB), 22.17 gC per m² below ground (BGB), and a total carbon stock of 4.21 tons per hectare. Based on this research, the preservation of seagrass ecosystems, which play a crucial role in mitigating climate change through CO₂ absorption, is essential.