Adult lobsters generally live in depths of less than 50 meters. However, some have been seen at depths of up to 700 meters. Lobsters prefer rocky bottoms covered with algae. This kind of habitat offers many cracks and shelters in which the lobster can hide (Photo below). It can also dig a burrow under a large stone. Algae make it easier for lobsters to hide, and they attract several organisms on which lobsters feed. Occasionally, adult lobsters can also be found on other types of bottoms such as vase, sand or gravel, but these are not the habitats they prefer. When there are no cracks or algae to shelter, lobsters dig a bowl-like depression in the soft substrates. Adult lobsters often stay close to the coasts in the summer because the water is warmer, and they migrate to open water in the winter to escape the turbulence.
Young lobsters (whose cephalothorax length measures less than 40 mm) stay generally close to the coasts at depths of less than 10 meters, on gravel and cobble bottoms. They can also be found on bottoms covered with mussel shells and algae. Young lobsters do not migrate to open water in winter. They remain hidden in their shelter during this season.
Shelters are important for lobsters, especially when they are small. They use them for protection against predators, waves and currents. Since lobsters are rather nocturnal animals, and they do not enjoy light very much, shelters are also used as protection against daylight. Sometimes, they have two accesses: a main entrance and a smaller one through which they can escape. Lobsters always remain in the entrance of their shelters with their claws in front of them ready to defend themselves.