Pre‐mobile infants and caregivers spontaneously engage in a sequence of contingent facial expressions and vocalizations that researchers have referred to as a social “dance.” Does this dance continue when both partners are free to move across the floor? Locomotor synchrony was assessed in 13‐ to 19‐month‐old infant–mother dyads (N = 30) by tracking each partner’s step‐to‐step location during free play. Although infants moved more than mothers, dyads spontaneously synchronized their locomotor activity. For 27 dyads, the spatiotemporal path of one partner uniquely identified the path of the other. Clustering analyses revealed two patterns of synchrony (mother‐follow and yo‐yo), and infants were more likely than mothers to lead the dance. Like face‐to‐face synchrony, locomotor synchrony scaffolds infants’ interactions with the outside world.