People use the Internet for a wide range of online sexual activities (OSA): behaviours that involve sexual content, topics, and stimuli. Yet, current OSA summary statistics provide little perspective on patterns of OSA experience because researchers have not compared multiple indicators of experience within the same sample. We explored the prevalence, variety, and frequency of young men and women's experience with three OSA subtypes: non-arousal (e.g., accessing sexual health information), solitary-arousal (e.g., viewing pornography), and partnered-arousal (e.g., sending sexually explicit messages). We examined patterns in experience with specific OSAs, subtypes of OSAs, OSAs overall, and differences related to gender across the lifetime and recently. Young adults (N=239) at a Canadian University completed a survey that included a new measure of 48 specific OSAs, representing the three subtypes. All participants reported at least one OSA experience in their lifetime (ranging 1–38). Although the prevalence and variety of experience was greater across the lifetime than recently, this difference was small and the pattern of results remained the same. Frequency of experience appeared greater for specific OSAs compared to OSA subtypes or overall. Frequency of specific OSAs were greater for the subgroup of participants who had engaged in the activity recently compared to the full sample. Significantly more men than women reported solitary-arousal OSA, and men reported greater variety and frequency of this subtype. This gender difference in prevalence and frequency only held for viewing sexually explicit pictures and videos online. We discuss implications for sexual scripts, researchers, clinicians, and educators.