The purposes of the present study were to examine the domain specificity of flow and its relationships with different motivation regulations in sport and academic. The sample consisted of 224 competitive student-athletes (126 males, 97 females, 1 missing) from Singapore universities with mean age of 22.73 years (SD = 2.76). Data was collected through a self-reported questionnaire to assess seven motivation types in Self-Determination Theory (SDT) and flow disposition in sport and academic domains. Findings revealed that there is a positive link between flow in sport and in academic at a cross-domain level. In addition, male student-athletes reported higher flow tendencies in both sports and academics. Male student-athletes in individual sport reported higher intrinsic motivation (IM) to accomplish and flow tendencies than male in team sport, but female student-athletes in team sport reported higher IM to accomplish and flow tendencies to accomplish than individual sport. IM to experience stimulation positively predicted flow in sport, while in academic domain, IM to know and identified regulation are positive predictors of flow. The findings of this study showed that IM to experience stimulation in sport and academic domains could positively predict flow.