Adaptations of organisms to different environments may be important in view of different stressors caused by climate change. Antarctic lichens provide a good model for studying resistance to environmental extremes. Our goal was to compare changes in water storage of Caloplaca regalis from two different localities in Antarctica. King George Island (KGI) and Deception Island (DI). DI is of particular interest owing to the unique microclimate of the volcanic island. The molecular dynamics of the residual water was monitored by 1H-NMR relaxometry, spectroscopy, and sorption isotherm analysis. Hydration kinetics for both samples distinguished three water fractions, (i) very tightly bound, (ii) tightly bound, and (iii) loosely bound water. However, hydration kinetics for C. regalis from KGI are faster than those from DI. Only one, averaged, water fraction was fitted for the 1H-NMR signal of mobile protons. Lichens from both environments contain a solid water-soluble fraction. The dissolution effect is detected with the saturation concentration varying around cs = 0,6(1) corresponding to sucrose, galactose or xylose for the KGI sample and cs = 0.3(1) corresponding to mannitol or galactitol for the DI sample. This suggests that C. regalis employs similar defensive strategies against desiccation but uses different substances for them.