Abstract This study revisited 158 documented active subglacial lakes across Antarctica, applying a height‐change anomaly delineation algorithm to CryoSat‐2 and ICESat‐2 satellite altimetry data to assemble a 14.75‐year (2010.5–2025.25) time series of active subglacial lake dynamics. We generated time‐evolving lake outlines at quarter‐year intervals that revealed spatiotemporal variability, including lake expansions and migrations. Evolving outlines enabled improved estimates of subglacial water volume change. We found that the previous method of using stationary outlines underestimated cumulative volume change between ∼ ${\sim} $4.8–7.4 km3 ${\text{km}}^{3}$ (65–100% $\%$ of the volume change estimated using evolving outlines) compared to evolving outlines when integrated across Antarctica. Evolving lake outlines also enabled the generation of a novel time series of subglacial lakebed active area, which we leveraged to estimate time‐varying dissolved inorganic carbon production.