A record of Rana temporaria on the ice cover of the Gulf of Finland is described. Frog slowly moved on the ice surface with speed around 0.03 m/s. Air temperature near ice surface was +3.5°C, and the frog body temperature was +4°C. In the Saint Petersburg region, common frogs can hibernate in the coastal waters of Baltic Sea with salinity of 0 – 5.8‰.