Antarctica's subglacial hydrological system is a unique and still largely unexplored source of geological, paleoclimatic, and biological information that can be accessed only through direct investigation involving the sampling of water, suspended particulate matter, and bottom sediments. Of greatest scientific value are sites that have remained isolated for hundreds of thousands of years and preserve continuous sedimentary sequences containing thick deposits of ancient bottom sediments unaffected by basal glacial erosion. Such sites occur in subglacial lakes, which are key components of Antarctica’s subglacial hydrological system. The planning and implementation of direct investigations of Antarctic subglacial lakes beneath both relatively thin ice and more than 2500 m of ice remain subjects of debate because experience with such operations is limited and there is no consensus on how compliance with environmental requirements should be ensured and monitored when subglacial environments are accessed. This article synthesizes the results of interdisciplinary studies of Antarctic subglacial lakes, including their locations, depths below the ice surface, morphometric and hydrodynamic parameters, and bottom-sediment composition. Particular attention is given to the technologies and equipment used to investigate subglacial lakes, including geophysical surveys, access-borehole drilling, lake access, measurement of the water body's physical and chemical parameters, and sampling of water, bottom sediments, and suspended particulate matter. The challenges and constraints associated with investigating “stable” subglacial lakes are analyzed and discussed, and key priorities for advancing the relevant technologies and equipment are identified.