The dynamics of land cover changes on Sulawesi Island have been analyzed to assess their impact on water regulation ecosystem services. This research aimed to spatially map the temporal evolution of these services from 1990 to 2022, employing a comprehensive dataset of natural landscapes, vegetation, and land cover patterns. Findings indicate that the island initially maintained a high capacity for water regulation, predominantly classified as high or very high in 1990. However, a significant decline was observed, with the island shifting to predominantly medium classes of water regulation services by 2022. Central and South Sulawesi experienced the most significant decreases in service capacity, while Southeast Sulawesi and Central Sulawesi exhibited some improvement in recent years. The spatial analysis elucidated the interplay between environmental changes and the provision of ecosystem services, emphasizing the profound influence of anthropogenic land cover alterations. The loss of vegetated areas and the increase in agricultural and urbanized land have been linked to the decrease in water regulation services, with direct implications for flood risk, water availability, and watershed health. The study highlights the importance of ecological carrying capacity as an indicator of regional sustainability, reflected in the fluctuating levels of water regulation services. The research concludes that the downward trend in water regulation services necessitates a strategic focus on restoration and conservation efforts to ensure the long-term viability of environmental and human systems. Policymakers are urged to consider these findings in the development of land cover policies, emphasizing the necessity of maintaining ecosystem service levels to support the island's environmental carrying capacity and resilience. Future work should continue to monitor these trends and investigate the efficacy of conservation interventions, thereby contributing to the global understanding of land cover impacts on ecosystem services.