Like all "Sterna" terns, the common tern feeds by plunge-diving for fish, from a height of , either in the sea or in freshwater lakes and large rivers. The bird may submerge for a second or so, but to no more than below the surface. When seeking fish, this tern flies head-down and with its bill held vertically. It may circle or hover before diving, and then plunges directly into the water, whereas the Arctic tern favours a "stepped-hover" technique, and the roseate tern dives at speed from a greater height, and submerges for longer. The common tern typically forages up to away from the breeding colony, sometimes as far as . It will follow schools of fish, and its west African migration route is affected by the location of huge shoals of sardines off the coast of Ghana; it will also track groups of predatory fish or dolphins, waiting for their prey to be driven to the sea's surface. Terns often feed in flocks, especially if food is plentiful, and the fishing success rate in a flock is typically about one-third higher than for individuals.