In the 21st century, use of online communication has skyrocketed, and this is particularly true for young people who have grown up in the age of the smartphone. In the world of online communication, adolescents and young adults especially seem to gravitate toward social media. The present study examined a mediational model wherein social media use in emerging adults predicts social media addiction through altered social behaviors, including face-to-face interactions, communication apprehension, and social skill deficits. More than 100 undergraduate students reported on their social media use and social behaviors via an online questionnaire. Contrary to expectations, social media use was only significantly correlated with social skills deficits, r(108) = .204, p = .017, and social media addiction, r(108) = .495, p < .001. Face-to-face interactions, communication apprehension, and social skills deficits did not function as mediators of the relationship between social media use and addiction and had no significant correlations with social media addiction. A modified mediation model is proposed, wherein impoverished face-to-face behavior and communication apprehension predict social skills deficits and those deficits predict social media addiction only when social media use is high.