Circumpolar Active Layer Monitoring – South (CALM-S) site was established in February 2014 on James Ross Island as the first CALM-S site in the eastern Antarctic Peninsula region. The site located near the Johann Gregor Mendel Station is labelled CALM-S JGM. The grid area is gently sloped ¬< 3° and elevated between 8 to 11 m a.s.l. Lithology of the site is formed by more muddy sediments of Holocene marine terrace and clayey sandy Cretaceous sedimentary rocks, which significantly affect texture, moisture content and physical parameters of the ground on the grid. Our objective was to study seasonal and interannual variability of active layer depth and thermal regime on CALM-S site and at two ground temperature measurement profiles AWS-JGM and AWS-CALM located in the grid. Average air temperature in the period March 2013 to February 2016 reached -6.8 °C. Average ground temperature decreased with depth from -5.1 °C to -5.3 °C at 5 cm to -5.5 °C to -5.9 °C at 200 cm. Active layer thickness defined as the depth of 0 °C isotherm was significantly higher at AWS-CALM between 86 cm (2014/15) and 87 cm (2015/16), while at AWS-JGM reached only 51 cm (2013/14) to 65 cm (2015/16). Mean probed active layer depth increased from 66.4 cm in 2013/14 to 78.0 cm in 2014/15. High differences were observed when compared minimum (51 cm to 59 cm) and maximum (100 cm to 113 cm) probed depth. The distribution of active layer depth at CALM-S JGM clearly shows the effect of different lithological properties between the two lithologically distinct parts of the grid.