This study investigates the redox geochemistry and soil characteristics of the Caimpugan Peatland within the Agusan Marsh Wildlife Sanctuary, Mindanao, Philippines. The ability of these peatlands to accumulate and preserve carbon is shaped by these processes that regulate microbial and geochemical activity. Despite the ecological importance of these systems, the redox geochemistry of peatlands in the Philippines remains poorly studied, especially in understanding how local peat environments function as carbon sinks. Peat cores were collected from various forest types and depths, reaching up to 5 meters below the surface, to evaluate gravimetric moisture status, redox, and geochemical conditions. The study revealed that the maturity of the peat grades, ranging from fibric peat in the upper layers to clayey peat in the lowest sections, reflecting past changes in water conditions and organic matter input that affect microbial activity and redox processes. The peat exhibited a very high moisture content, reaching up to 384.34%, indicating persistent saturation and limited oxygen diffusion, favoring the buildup and preservation of organic material. Redox analyses revealed that 7.4% of the samples fell within the iron reduction zone, primarily near the surface, while 92.6% fell within the sulfate reduction zone. The strong dominance of sulfate-reducing conditions suggests a highly reduced environment where most available electron acceptors are depleted. Redox potential values were observed to nearly reach the threshold of methanogenesis, reflecting extremely low oxidation states typical of stable carbon-preserving systems. Geochemical results identified major oxides, including SiO₂, Al₂O₃, SO₃, Fe₂O₃, TiO₂, P₂O₅, CaO, and MgO, which influence nutrient exchange, buffering capacity, and redox balance. Overall, the Caimpugan Peatland shows consistently reduced, saturated, and chemically stable conditions that support long-term carbon storage. These findings provide a clearer understanding of peatland redox environments in the Philippines and their role in sustaining carbon reservoirs under natural tropical conditions.