Social media (SM) users are a combination of several behaviors across platforms. Patterns of SM use across platforms may be a better indicator of risky drinking than individual behaviors or sets of behaviors examined previously. This longitudinal study addressed this gap in the literature using latent profile analysis (LPA) to identify subpopulations of SM users during the college transition (N=319). Indicators included in the LPA were general SM (checking, time spent, and posting to Instagram/Facebook/Snapchat; Finstagram ownership) and alcohol-related posting (alcohol, partying, and marijuana content) behaviors. LPA results revealed three SM user subpopulations at baseline: low general use with low alcohol-related posting (LGU+LAP), and high general use with low alcohol-related posting (HGU+LAP) or high alcohol-related posting (HGU+HAP). Baseline drinking, injunctive norms, and alcohol beliefs were associated with greater odds of HGU+HAP membership. Prospective analyses revealed that HGU+HAP was associated with greater alcohol use and consequences relative to HGU+LAP and LGU+LAP. Results suggest that there are distinct patterns of SM use during the college transition associated with risky drinking that can inform interventions combating SM-related alcohol risks. These findings also illustrate the importance of analyzing multiple SM user behaviors across multiple platforms simultaneously in future studies.