How fast can penguins swim?

According to Falklands Conservation, penguins can swim at speeds of up to 17 mph; however, they normally average between 9 and 15 mph. Penguins can also dive further and swim faster than any other bird.

According to About.com, penguins jump in shallow arcs in the air while swimming, which is a practice known as "porpoising." This practice covers their plumage with tiny air bubbles and allows them to reduce friction while swimming and avoid predators. Some scientists theorize that penguins engage in this practice simply because they are happy. Penguins feed on fish, shrimp, krill and other crustaceans, and their superior underwater eyesight allows them to spot prey even in cloudy or murky water.