Methanol is one of the most abundant oxygenated volatile organic compounds in the atmosphere and microbial methanol metabolism is an important part of the marine carbon cycle. However, only limited studies existed about methanol cycling in marine waters, and the sources and sinks of methanol remains largely unconstrained in the Pacific Ocean. In this study, we investigated the methanol abundance and combined radiotracer approach to constrain the pathways and dynamics of methanol cycling in the northwest Pacific Ocean.       Methanol was detected in relatively low concentrations (< 12 nM to 391 nM) in the Kuroshio-Oyashio extension (KOE) region, which could be attributed to rapid biological turnover. Oxidation rates (0.9 to 130.5 noml L^-1 d^-1) were much higher than the assimilation rates (0.09 to 6.83 noml L^-1 d^-1), indicating that >89.7% methanol was used as an energy source. Total methanol uptake rate ranged from 1.0 to 130.7 noml L^-1 d^-1, suggesting turnover times as low as 5 days (3 to19 days). Surface water in the KOE region acts as a net methanol sink to the atmosphere at most sites (average flux: 9 μmol m^-2 d^-1), and atmospheric deposition accounted for 17.2% of microbial consumption in the mixed layer. These results provide insights into the dynamics of microbial methanol cycling in pelagic waters.