Background: Developmental theorists suggest that physical activity during early childhood promotes fundamental motor skill (FMS) proficiency; and that differences in FMS proficiency are largely related to children's experiences. Aim: To examine associations between participation in different types of recreation/ leisure and FMS proficiency of boys and girls in their first year of school. We hypothesized that there would be positive associations between FMS proficiency and participation in organized sport, physical activities, and active physical recreation; but not for other types of recreation/leisure. Method: Participants (n ¼ 74) were kindergarten children (Mage ¼ 5y11 m; boys ¼ 55%). Parents completed the diversity dimension of the Children's Assessment of Participation and Enjoyment (CAPE) survey. The CAPE measures children's participation in everyday activities outside of mandated school activities in the past four months in five types of formal and informal activities, specifically: Recreational activities, Physical activities, Social activities, Skill-Based activities, and SelfImprovement activities. Two categories of activities were also reported: Organized Sport and Active Physical Recreation. Locomotor and object control skills were assessed using the Test of Gross Motor Development-2 and static balance was assessed using a stork stand. Sex-based differences in motor skills and participation were examined using chi-squared analyses. Correlation coefficients were used to examine relationships between motor skills and CAPE sub-domains and categories. Linear regression was used to examine whether the type of activity predicted motor skill proficiency and the reverse. Results: There were no sex-based differences in locomotor skills; whereas boys' object control skill scores were significantly higher than girls, and girls' stork stand scores were higher than boys'. Although there were no sex-based differences in the more active categories of recreational pastimes; girls participated in significantly more formal and informal dance and the prevalence of participation in team sports was significantly higher for boys. For boys, participation in physical activities predicted both locomotor and object control skill scores, organized sport predicted object control skills, and active recreation predicted stork stand times and object control skill scores. These relationships were not evident among the girls. Conclusions: These findings illustrate that young children participate in a narrower array of physically active recreational pursuits compared with less active pursuits. There were notable sex-based differences in the relationships between participation and motor skill proficiency. For girls, none of the associations between recreational pastimes and motor skill proficiency were significant. This suggests that the motor proficiency of girls, as assessed in this study, is neither a precursor to, nor an outcome of, participation in active recreational pastimes. Contrastingly, the findings for boys support theory t...