A century of research has described the development of walking based on periodic gait over a straight, uniform path. The current study provides the first corpus of natural infant locomotion based on spontaneous activity during free play. Locomotor experience was immense: 12- to 19-month-olds averaged 2368 steps and fell 17 times/hour. Novice walkers traveled farther faster than expert crawlers, but fall rates were comparable, suggesting that increased efficiency without increased cost motivates expert crawlers to transition to walking. After walking onset, natural locomotion dramatically improved: Infants took more steps, traveled farther distances, and fell less. Walking was distributed in short bouts with variable paths—frequently too short or irregular to qualify as periodic gait. Nonetheless, measures of periodic gait and natural locomotion were correlated, indicating that better walkers spontaneously walk more and fall less. Immense amounts of time-distributed, variable practice constitute the natural practice regimen for learning to walk.