Extensive petroleum development over the past century has resulted in a large inventory of legacy oil and gas wells across Canada. While most of these wells remain stable following abandonment, documented cases of gas migration highlight the need for improved diagnostic approaches to assess subsurface conditions and potential leakage pathways in a natural environment. This study examines the shallow subsurface conditions associated with persistent methane leakage around decommissioned oil and gas wells. Geophysical and geochemical measurements were collected at a decommissioned exploration borehole site in contrasting seasonal conditions near Cecil Lake, British Columbia. Electrical and electromagnetic measurements were collected simultaneously with methane gas flux, soil gas sampling, and microbial community analysis to evaluate shallow soil conditions around the well and an associated methane hotspot. Measurements were collected in early-May and late-November, representing seasonally dry and wet soil conditions. Time-lapse 2-D and 3-D electrical resistivity tomography and induced polarization measurements were collected seasonally and diurnally to evaluate potential geophysical dynamics associated with gas efflux and microbial activity. Spatial electromagnetic induction surveys supported spatial characterization of geophysical anomalies. Additionally, completed geochemical (soil gas), gas efflux measurements, and microbial diversity analyses supported interpretation of geophysical results. Preliminary findings suggest a seasonally persistent geophysical and geochemical anomaly with orders of magnitude larger than its associated methane gas efflux footprint. Geophysical and geochemical anomalies were also associated with an increased diversity of microbial communities, which is consistent with a gas oxidation halo around the primary methane efflux pathway.