The common seal inhabits the river mouth in the sea where the water is slightly salty and rich in fish and birds, as well as shallow waters near the shore where the water rises and falls, and crabs live. The species prefers marine environments, coastal waters, the benthic coastal zone, and the near-bottom coastal zone. The common seal's habitat is associated with cold seas where there may be ice in winter and it is not hot in summer, as well as conditions of constant humidity. The species is found in temperate seas where the water is cool or warm, it is cold in winter, comfortable to swim in summer, and in zones with a warm summer and abundance of rains, as well as in places with a warm summer and not very cold winter.