Nutrient cycling and nutrient limitation determine primary productivity, changes in vascular and non-vascular plant cover, microbial community composition, and decomposition rates in peatlands. While nitrogen (N) in peatlands is well-studied and considered the limiting nutrient in bogs, much less is known about phosphorus (P). For example, an increase in N-addition, e.g., via atmospheric deposition, may lead to phosphorus becoming the limiting nutrient.Soil microbes mediate P cycling between organisms and soil pools, but how these cycles change through the year in peatlands is unknown. To answer this question, samples from Mer Bleue Bog near Ottawa, Ontario, are taken throughout the year to capture seasonal variation of microbial phosphorus and available phosphorus. Phosphorus readily available to microbes and plants is measured with anion exchange resins in water, and microbial phosphorus is measured using combined hexanol fumigation/anion exchange resin extraction. Results from summer and autumn of 2022 show large temporal variation in resin-extractable and hexanol-labile phosphorus. In general, hexanol-labile phosphorus levels were higher in upper layers of peat, while resin-extractable phosphorus tended to be more concentrated in deeper layers. Furthermore, resin-extractable and hexanol-labile phosphorus levels vary substantially through the year, which has implications for the ecology of peatlands experiencing nutrient addition. We attribute these variations to an efficient biological cycling of P in the top layers of the peat and to seasonal fluctuations of the hydrological regime.