Swimming is the act of moving through the water by using the arms, legs, and body in motions called strokes. The most common strokes are the crawl, backstroke, breaststroke, butterfly, and sidestroke. Swimming is an integral part of almost all water-based activities. It is also a competitive sport itself.

Some scientists believe that human beings are born with an instinctive ability to use their arms and legs to stay afloat. That instinct, however, disappears within a few months after birth. Later in life many children and adults learn to swim in order to be safe around the water, to have fun, and to participate in competition.