Objective Decreasing intentional tanning behaviour is a critical area of skin cancer prevention. Research evidence that tanning behaviour is significantly influenced by appearance motivations exists. The Tripartite Influence Model posits that internalisation of ideals about body image mediates the relationship between sociocultural norms and appearance‐related behaviour and has been demonstrated primarily in the domain of weight. This study aimed to assess whether ideal skin tone (internalisation of a tanned ideal) mediated the endorsement of sociocultural norms about attractiveness of tanned skin and 12‐month tanning behaviour. Method Young adult participants (N = 514) from the university (removed for blind review) were surveyed regarding their ideal skin tone and sociocultural norm endorsement. Results At 12‐month follow‐up, 246 participants reported their tanning behaviour over the previous year. Results indicated that the internalisation of a tanned ideal mediated the relationship between sociocultural norms and tanning behaviour for females but not males. Young adult males also desired a tanned appearance, and peer sociocultural perceptions were associated with male tanning behaviour. Conclusions This research lends support to the proposition that the Tripartite Influence Model has explanatory power for tanning behaviour. We recommend that future research involving young adults incorporate skin tone and tanning as a component of body image alongside body shape and eating behaviours.