Samples from the upper 300 m along the 52°S band, south of the Antarctic Polar Front in the Atlantic sector of the Southern Ocean, including a 3‐week monitoring of a persistent bloom, were analyzed to advance our understanding of iron cycling and supply to recurrent phytoplankton blooms. We measured dissolved Fe (dFe, <0.2 μm) and labile particulate iron using a mild acid leach (pLFe 48h ) targeting primarily detrital and fecal material. Particulate iron was partitioned into size classes to distinguish small, “slow” sinking particles (<53 μm) from large, “fast” sinking particles (>53 μm), while intermediate fractions were analyzed to investigate aggregation and export processes. Across all stations, dFe exhibited a consistent vertical structure, including a previously undescribed ubiquitous minimum below mixed and euphotic layers. The absence of pLFe 48h in the 0.2–3 μm fraction indicates reduced aggregation and is consistent with minimal authigenic Fe formation. Instead, pLFe 48h was concentrated in “slow” sinking particles, indicating surface entrainment. Biomass was negatively correlated with dFe but positively correlated with pLFe 48h , linking bloom development to particulate iron availability rather than dFe. Overall, rapid surface recycling of “slow” sinking pLFe 48h appeared to meet most of the daily iron demand during a prolonged diatom bloom. Near South Georgia Island, wind‐driven mobilization of iron‐rich material from the island snowpack and deposition into leeward waters likely supplied an additional iron source. By applying new protocols to characterize labile particulate iron, we reveal the elusive magnitude of the recycling dynamics of particulate iron in fecal and detrital materials sustaining Southern Ocean blooms. Plain Language Summary Owing to its scarcity, iron is crucial in regulating life distribution across large regions of the ocean surface. Yet in the Atlantic sector of the Southern Ocean, the mechanisms supplying iron to support the region's frequent phytoplankton blooms remain insufficiently understood. To investigate these processes, we applied a mild acidification method to filtered and unfiltered seawater, allowing us to determine iron in particles such as fecal material and cellular debris aggregates, apart from cellular and mineral forms. This approach revealed an unexpected, widespread minimum of dissolved iron just below the sunlit surface layer (60–100 m), alongside a predominance of detrital and freshly formed particulate iron within “slow‐sinking” particles. This combination is critical for recycling particulate iron in surface waters before iron sinks too deep for photosynthetic organisms' reutilization. Additionally, strong winds over South Georgia Island likely resuspended iron‐rich particles trapped in snow on the island's crest, adding more iron to nearby waters. This research highlights the importance of recycled biological particles in sustaining ocean productivity and emphasizes the need for novel analytical protocols to study how iron moves through diverse particle types in the ocean. Key Points Dissolved iron showed a consistent subsurface minimum just below the mixed and euphotic layers across contrasting biochemical regimes Slow‐sinking leachable particulate iron supplied bioavailable iron to local blooms, with additional input leeward of South Georgia from wind Rapid recycling of fecal and cellular debris, but not authigenic Fe, supplies bioavailable Fe for blooms