Research on people's motives for engaging in high-risk activities has typically been viewed through the single-focused lens of sensation seeking. We provide evidence that comprehensively challenges that view. First, we develop and confirm the structure of a 3-factor measure of motives: the Sensation Seeking, Emotion Regulation, and Agency Scale (SEAS; Study 1). We then use the SEAS to provide evidence of differential motives for 2 high-risk activities: skydiving and mountaineering. The motive for skydiving is strongly associated with sensation seeking; the motive for mountaineering is strongly associated with emotion regulation and agency but not with sensation seeking (Study 2). We also show that these conclusions cannot be drawn from existing measures of personality and sensation seeking (Study 3). Finally, individuals who are motivated by emotion regulation and agency needs also have greater expectations regarding their emotion regulation and agency. It is these greater expectations that most successfully discriminate mountaineers from skydivers and control participants (Study 4). It is concluded that researchers should no longer consider risk takers as a homogenous sensation-seeking group and that they should consider risk taking as a potential model of human endeavor. The SEAS can be used as a measure of motives for behavior whenever sensation seeking, agency, or emotion regulation is thought to be at the core of such motives, and the results are discussed in the context of encouraging personality researchers to consider the specific spontaneous behaviors that motivate different people.