Affiliation between interacting partners is associated with a high level of behavioural synchronization in many species. Pet dogs are known to share strong affiliative bonds with their owners and to synchronize their behaviour with them when moving freely indoors. Surprisingly, outdoor dog-human interspecific synchronization has seldom been investigated. We therefore explored whether, when allowed to move freely in a familiar outdoor space, dogs synchronize their behaviour with their owners' movements. We found that dogs visibly synchronized both their location (staying in close proximity) and their activity (moving when their owner moved, and at the same pace, and standing still when their owner stood still) with those of their owners. By demonstrating that owners act as attractors for their dogs in an outdoor space, the present study contributes new data to the understanding of interspecific behavioural synchronization.