Background: Despite the transition to university offering a treatable moment to intervene in healthy behaviors, participation in sport declines when students begin higher education. Although key belief targets have been identified within formative research using the Theory of Planned Behavior, the precise content of the intervention remains unclear. Purpose: The purpose of this study was to use focus groups to identify the reasons and solutions to previously identified key beliefs and potentially effective behavior change techniques (BCTs). This information can then be used in the development of a theory-based behavior change intervention. Method: A purposive sample of 22 first-year undergraduate students (n = 8 men; M = 19.8 years, SD = 1.3) attending a university in the North of England (United Kingdom) was used. Focus groups were audio-recorded; recordings were transcribed verbatim, analyzed thematically, and coded for recurrent themes. Results: The data revealed 14 reasons regarding enjoyment, 11 reasons for friends' approval, 11 reasons for friends' own participation, 14 reasons for the approval of family members, and 10 solutions to time constraints. Twelve distinct BCTs were suggested to address these reasons and solutions. Conclusion: This study provides important information that will inform the content of an intervention promoting student participation in sport.