Informal learning experiences can provide PK-12 students with the opportunity to enhance their learning of, attitudes toward, and interest in STEM. This study explored the impact of informal STEM learning experiences on Latinx high school students. Through an authentic STEM program, we investigated how students' science and engineering skills, practices, and knowledge were influenced, as well as their attitudes and interest in STEM. Additionally, we examined the transferability of their learning from informal to formal educational settings. Our findings indicated that this innovative approach enhanced student learning of science and engineering practices, positively shaped their attitudes toward STEM, and facilitated metacognitive transfer to formal learning environments.