AbstractAntarctica's basal water system contains more than 130 active lakes, and its evolution remains a major uncertainty in future ice sheet dynamics. Most of our current understanding has come from using satellite radar and laser altimetry acquired since 2003. NASA's ICESat‐2 laser altimetry mission, launched in September 2018, provides a new, small‐footprint altimetry data set with which to investigate Antarctic active subglacial lake processes. Here, we demonstrate the ability to continue monitoring active subglacial lakes at timescales shorter than the ICESat‐2's repeat cycle and generate self‐consistent time series of subglacial lake surface‐height anomalies from combined ICESat, CryoSat‐2, and ICESat‐2 altimetry. Focusing on three regions with the known significant lake activity, we show that ICESat‐2 laser altimetry can not only extend the record of subglacial lake activity but also provides better understanding of hydrological processes by capturing denser and more precise spatial detail.