Recently, a new ‘athletic ideal’, characterised by both thinness and visible muscle tone, has emerged as the modern appearance ideal for women to aspire to (Robinson et al., 2017; Rodgers et al., 2018). Women who epitomise the athletic ideal online are often shown to be engaging in exercise. Promoting health and fitness demonstrates the potential for considerable positive influence, however recent experimental research has found women exposed to the athletic ideal are more frequently dissatisfied with their bodies. In an attempt to alleviate media-induced body dissatisfaction, there has been a shift towards exploring the potential for media imagery to transmit positive body image ideals. This shift has been reflected online with increased female body diversity content. The present study sought to experimentally investigate the impact of athletic ideal versus diverse body ideal fitness-content on young women’s body image, mood, physical functionality satisfaction, and exercise intent, under the framework of Social Comparison Theory. Ninety-five female participants (aged 18-25 years) were randomly assigned to view either athletic ideal exercise videos, diverse body ideal exercise videos, or scenic travel (control) videos. Results showed that acute exposure to athletic ideal videos led to increased body dissatisfaction and less physical functionality satisfaction compared to exposure to diverse body ideal or control videos. Comparatively, viewing diverse body ideal videos led to improved body dissatisfaction, physical functionality satisfaction, and greater exercise intentions. As this study is the first to provide empirical evidence of the effects of diverse body ideal fitness imagery, it illuminates a number of future research directions. These are discussed, along with the theoretical and practical implications of the study’s findings.