Introduction: While enrollment in swimming lessons is associated with lower drowning risk in children, many parents do not enroll their children in formal lessons. To understand these decisions, the current research investigated the social cognition factors that drive parents’ intentions to enroll their children for the first time. Methods: Using a mixed methods design, beliefs about enrolling one's child in swimming lessons were elicited in a sample of 22 Australian parents. A second sample of 323 then rated the extent to which they agree with each of these beliefs and completed measures of an extended theory of planned behavior (TPB) model including autonomous motivation, risk perception, and role construction. Results: Results showed a range of behavioral, normative, and control beliefs to significantly predict intention to enroll. In the model, subjective norm, perceived behavioral control, risk perception, and role construction all predicted intention to enroll. Autonomous motivation had an indirect effect on intention via the TPB constructs. Conclusions: Targeting beliefs that non-enrollment places a child at risk, that enrollment is under a parent's control, that others would want parents to enroll their child, and that it is the responsibility as a parent to enroll their child may be viable messages for intervention. Practical implications: Current results signpost several potential belief-based targets for interventions encouraging enrollment in swimming lessons. However, as qualitative data also indicated structural barriers to enrolment, such strategies should be paired with attempts to ensure swimming lessons are affordable and accessible to the wider population.