Polar lakes respond quickly to climate-induced environmental changes. We studied the chemical limnological variability in 127 lakes and ponds from eight ice-free regions along the East Antarctic coastline, and compared repeat specific conductance measurements from lakes in the Larsemann Hills and Skarvsnes covering the periods 1987–2009 and 1997–2008, respectively. Specific conductance, the concentration of the major ions, pH and the concentration of the major nutrients underlie the variation in limnology between and within the regions. This limnological variability is probably related to differences in the time of deglaciation, lake origin and evolution, geology and geomorphology of the lake basins and their catchment areas, sub-regional climate patterns, the distance of the lakes and the lake districts to the ice sheet and the Southern Ocean, and the presence of particular biota in the lakes and their catchment areas. In regions where repeat surveys were available, inter-annual and inter-decadal variability in specific conductance was relatively large and most pronounced in the non-dilute lakes with a low lake depth to surface area ratio. We conclude that long-term specific conductance measurements in these lakes are complementary to snow accumulation data from ice cores, inexpensive, easy to obtain, and should thus be part of long-term limnological and biological monitoring programmes. Introduction Polar lakes act as 'early warning systems' because they respond quickly to climate-induced environmental changes (Hodgson & Smol 2008). In the Arctic and maritime Antarctica, where global warming is particularly amplified, the recent temperature rise has resulted in enhanced primary productivity in lakes (Quayle et al. 2002), a negative precipitation-evaporation balance (Smol & Douglas 2007a), and marked changes in their community structure (Smol et al. 2005). In particular, lakes with a high surface area to volume ratio were shown to respond quickly to changes in the precipitation-evaporation balance and are prone to salinization and desiccation (Smol & Douglas 2007a). In comparison to these regions, recent climate changes are relatively modest in East Antarctica (EA; Turner et al. 2009) and there are distinct regional differences in, for example, snow accumulation rates (Monaghan et al. 2006). Measurements on the Law Dome ice core show that snow accumulation rates have increased since 1970 and are now outside the natural variability of the past 750 years (Van Ommen & Morgan 2010). In contrast, in other EA regions, such as the inner part of the continent and in Dronning Maud Land, the volume of snow has decreased between 1995 and 2004 (Monaghan et al. 2006). The relatively modest 23