The reclamation of mature fine tailings (MFTs) that are by-products of oil sands extraction is an environmental and geotechnical challenge. Via augmenting the exogenous ureolytic bacterium Sporosarcina pasteurii, microbially induced carbonate precipitation (MICP) has been used to accelerate the dewatering and settlement process of fine tailings in previous studies. The observed performance of MICP-treated MFT may enhance the reclamation process; however, augmenting the tailings ponds may be too insurmountable to be accomplished at scale. Towards a new paradigm, we investigated if the indigenous microbes in MFT could be stimulated to stabilize MFT via ureolytic-driven MICP. We studied the influence of oxygen availability, initial pH, and inhibition of methanogens on the treatments. Physicochemical characteristics estimation, mineral identification, macro and fabric observation, and microbial community analysis were used to evaluate the behavior of untreated and treated MFT. The results demonstrated that in initially oxic condition and neutral pH medium the MICP-treated MFT specimens showed improvement of bearing support due to a heavy precipitate layer. Increased ammonium concentrations, accumulated precipitates, minerals alteration, elevated pH, and densified fabric in the treated groups demonstrated the degradation of urea, formation of calcite bonds, and stimulation of ureolysis in MFT. Microbial community analysis of MICP-treated MFT revealed a high relative abundance of Bacillus, speculating that Bacillus played a primary role for developing the ureolytic MICP treatment in MFT. This study shows that stimulation of indigenous ureolytic microorganisms in MFT may provide a novel alternative to densify MFT via MICP.