Methane emissions stemming from waste management facilities pose a significant concern for global warming. This study aimed to develop, construct, and monitor an advanced biocover system to mitigate fugitive methane emissions from a closed landfill situated on Kudjape, Sareemaa Island, Estonia. Over a monitoring period of 10 years following the biocover implementation, changes in methane emissions were meticulously documented. The biocover substrate comprised a mixture of fine fraction obtained from landfill mining, natural soil, and sewage sludge in a ratio of 3:1:1. Methane emissions were monitored both at the surface and at depths ranging from 25 cm to 2 m within the biocover layer at three different locations. The data collected from three gas wells illustrated distinct scenarios within the landfill environment: Gas well K1 depicted an optimistic scenario, showing a consistent reduction in methane intensity over time following the biocover installation. Gas well K2 indicated a potential hotspot within the landfill, characterized by significantly elevated methane concentrations. Gas well K3 exhibited minimal methane presence, suggesting effective mitigation in that specific area. These varied findings underscored the heterogeneous nature of waste composition and gas distribution within the landfill. Despite differing scenarios across monitoring locations, an overall reduction in methane concentration was observed, highlighting the effectiveness of the biocover in mitigating methane emissions.