Locomotion within mollusks can vary as there are many different classes of mollusks. The type of locomotion of the mollusks is defined by the type of food they have.

Gastropods and herbivorous mollusks are the types that secrete a slime trail and slide over it by contracting their muscular foot. These include snails, whelks, periwinkleunbs, and slugs, the terrestrial forms of mollusks. Their foot is divided into three parts longitudinally. The central foot that holds the activity of the locomotor, is the foot which glides on the mucous track.

Bivalves, the two hinged shelled mollusks, are mainly sessile, do not move. They usually do not move and bury themselves under the earth. When naturally disasters and changes occur they are more likely the ones to be in danger, while other animals are able to swim from harm, whereas they have to take time to dig out themselves and move away.

If required to move, bivalves share the same method of movement as cephalopods, ones with a distinct head and a set of arms or tentacles. These use propel themselves through the use of jet propulsion. Jet propulsion was introduced in the Paleozoic era when the fish population increased and efficient motion was needed. The jet is supplemented with a fin motion where the thrust is more amplified when the fins flap when the jet is released. The mantle cavity is filled with oxygenated water, then passed to the gills from the contraction of a muscle, the water is expelled.

Herbivorous mollusks usually move slower than carnivorous mollusks. The faster movements for carnivorous mollusks allow them to have a great advantage in catching their prey and the slower movements of herbivorous mollusks are more consistent in pace. Larger terrestrial mollusks move much slower than smaller mollusks.