In response to the growing solo travel market, this study developed a research instrument and collected empirical data to uncover the motivations and constraints affecting solo travel. Using a conceptual model based on the theory of planned behaviour and the findings of qualitative interviews, the main drivers of solo travel intention and the importance between the drivers were tested through a national survey conducted in Australia. Results revealed that (1) self-actualisation emerged as the most significant motivation for solo travel, (2) attitude was negatively associated with intrapersonal and interpersonal constraints, and (3) interpersonal constraints, followed by perceived behavioural control and overall attitude, were prominent in predicting behavioural intention. The findings offer a validated solo travel model for future research and have implications for tourism marketing strategies and products targeting existing and latent solo travellers.