OBJECTIVE: Dog ownership is positively associated with children's physical activity. It is plausible that dog-facilitated activity rather than dog ownership per se encourages children's physical activity behaviors. We examined relationships between dog walking and children's physical activity, and outdoor play and independent mobility. METHOD: Cross-sectional survey data from the 2007 Perth (Western Australia) TRavel, Environment, and Kids (TREK) project were analyzed for 727 10-12 year olds with a family dog. Weekly minutes of overall physical activity and walking, local walking and outdoor play were collected from children and parents. Children's weekly pedometer steps were measured. Independent mobility was determined by active independent travel to 15 local destinations. RESULTS: Overall, 55% of children walked their dog. After adjustment, more dog walkers than non-dog walkers walked in the neighborhood (75% vs. 47%), played in the street (60% vs. 45%) and played in the yard (91% vs. 84%) (all p ≤ 0.05). Dog walkers were more independently mobile than non-dog walkers (p ≤ 0.001). Dog walking status was not associated with overall physical activity, walking, or pedometer steps (p>0.05). CONCLUSIONS: Dog-facilitated play and physical activity can be an effective strategy for increasing children's physical activity. Dog walking may provide a readily accessible and safe option for improving levels of independent mobility.