Data from a hydrographic survey located in the Princess Elizabeth Trough, near the Antarctic continent (63-65 ° S, 85 ° E) are presented and discussed. This region is covered by sea-ice for most of the year with the ice-edge retreating to the southern edge of the Trough during summer. Water samples were collected during the Austral summer, February 1993, to determine the ratio of the oxygen-18 to oxygen-16 isotope, δ18O. Four water bodies are characterised by their temperature, salinity and δ18O properties, Surface Water (0.0-1.2 ° C, 33.1-34.0, -0.39‰), Winter Water (-1.7 ° C, 34.4, -0.39‰), Warm Deep Water (2.0 ° C, 34.69, 0.02‰) and Bottom Water (-0.43 ° C, 34.669, -0.25‰). The Bottom Water is warmer, saltier and heavier isotopically than Weddell Sea Bottom Water (-0.9 ° C, 34.65, -0.29‰); and has T-S properties close to that of classical Antarctic Bottom Water (-0.4 ° C, 34.66). This Bottom Water is isotopically distinct from the Weddell Sea derived Bottom Water that ventilates the Indian ocean through the Kerguelen-Crozet gap. A mechanism for local formation of the Bottom Water involving freezing of Surface Water and entrainment of Warm Deep Water is described.