Many schools aim to provide social and emotional learning (SEL) opportunities for students. SEL is important for positive youth development. However, it remains unclear how SEL skills might be influenced by adventure education in school settings. This study used a mixed-methods design to explore potential changes in teachers' perceptions of students' SEL during an adventure-based SEL program. Twenty-two fifth- and seventh-grade teachers completed questionnaires about their students three times a year for 3 years. Findings suggest an intentional adventure-based program aiming to build SEL skills can have modest influences on students' awareness of and prosocial behaviors toward themselves, others, and the collective. However, considering the school context, SEL can be limited by some students' struggles with self-regulation and awareness of others, and the negative behaviors of a few students can disproportionately affect the whole class. Implications include using adventure education approaches and activities that are responsive to dynamic situations in school settings.