Background: Practitioners want to create meaningful experiences for youth because they provide positive benefits. Immersion semester high schools are likely to provide meaningful experiences. Purpose: This study sought to identify what types of activities are most meaningful to youth, whether activities are more meaningful in immersion semester high schools, and to determine which aspects of immersion semester high schools predict meaningfulness and whether this varies by emotional valence. Methods: Youth (N = 261) provided 11,498 surveys (6,062 at program/5,435 at home) when they participated in an immersion semester high schools and when they were at home. They reported on the meaningfulness of experiences twice daily for 3 weeks in each context. Findings: The results showed that hanging out with peers was the most meaningful activity, that experiences in immersion semester high schools were more meaningful than at home, and that whereas higher levels of emotion predicted higher levels of meaningfulness regardless of how positive or negative the experience was, behavioral engagement was more predictive for positive experiences, whereas psychological engagement was more predictive for negative experiences. Implications: Immersion semester high schools can create more meaningful experiences than at home, especially those that are emotionally engaging.