The biologically available phosphorus (BAP) and soluble reactive phosphorus (SRP) concentrations and phosphorus (P) uptake rates within the euphotic zone (0–175 m) were measured on eight cruises between October 2000 and November 2001 to Sta. ALOHA (22.75°N, 158°W) in the North Pacific Subtropical Gyre. The SRP concentrations in the upper 100 m ranged from 7 to 84 nmol P L−1, with a mean concentration of 41 nmol P L−1 (SE = 4,n = 40). The BAP pool consistently exceeded the SRP pool by factors of 1.4–2.8 in the upper 100 m, the additional P amounting to 7–15% of the dissolved organic P (DOP) pool, assuming that the measured SRP pool is fully bioavailable. Mean P uptake rates, based on SRP concentrations, ranged from 0.8 to 4.0 nmol P L−1 d−1, with the highest rates in the surface waters decreasing with increasing depth. Mean P uptake rates that are based on BAP concentrations ranged from 0.6 to 8.0 nmol P L−1 d−1, with a maximum at ~45 m, the depth corresponding to the highest adenosine‐5′‐triphosphate concentrations and highest DOP: SRP ratios. In the 125–175‐m depth interval, SRP concentrations increased from 74 to 200 nmol P L−1 and DOP declined by an average of 70 nmol P L−1. Because of the lower DOP concentrations at these depths, the contribution to BAP from the DOP pool increased to ~25%. These results indicate that the microbial community utilizes combined P compounds for their P nutrition simultaneously and, on average, uses them to the same extent as SRP in the upper water column. These results have important implications for P biogeochemistry in low‐inorganic nutrient environments.