Self-presentation is consistently associated with physical activity (PA). With advances in identities and behaviours shaped by social media, it is important to explore the association between social media self-presentation (SMSP) and PA. SMSP has core facets of: online presentation (e.g., conveying authentic or inauthentic positive appearance information on social media), appearance-related activity (e.g.,commenting, sharing and liking appearance-related social media content) and appearance comparisons (e.g. tendency to evaluate one's appearance compared with others on social media). This study described SMSP and explored the facets as correlates of PA. Participants (N=286; 68% women, Mage±SD= 23.55±3.55 years) were recruited from Prolific and completed a self-report survey. Descriptively, participants spent M±SD=161.30±135.40 minutes on social media per week. Women reported higher (p < .01) online presentation (d = .77) and appearance comparison (d = .58) scores as well as less PA (d = .39) compared to men. The three facets of SMSP were correlated at r = .34 to .54, p < .001. Controlling for age and gender, appearance activity [b(SE) = .084(.031), p = .007] and appearance comparisons [b(SE) = -.065(.030), p = .03] were correlates of PA, F(5) = 4.41, p = .001. These findings suggest that more appearance focused social media activity and fewer appearance comparisons are related to greater PA. The results offer potential links between social media use and PA, and future work is needed to connect SMSP with motives and goals for PA.