Abstract Full - depth conductivity–temperature–depth/hydrographic measurements were taken in May – June 1995 along 28°15′, 35°15′, and 43°15′S from the Chilean coast to 86–88°W from the R.V. Sonne . Sections of potential temperature, salinity, neutral density, and oxygen are presented to illustrate the water-column structure in this sparsely sampled region. A more comprehensive database on all available hydrographic data from the region was compiled. These data and available meteorological data are used to help in the interpretation of the Sonne results. A number of important features found in the sections are discussed, including a shallow salinity minimum (apparently ventilated from south of ∼37°S), salt fingering as a possible mechanism to transport high-salinity subtropical water into the shallow salinity minimum, Equatorial Subsurface Water, Subantarctic Mode Water, and Antarctic Intermediate Water. Geostrophic calculations of alongshore flow show the poleward Peru – Chile Undercurrent at each of the three sections with a poleward descending core and peak velocities of ∼10 cm s −1 . As in earlier works, a deep Pacific outflow is found near the Chilean coast, part of a clockwise deep circulation in the Chile Basin.