Informal STEM learning experiences (ISLEs), such as participating in science, computing, and engineering clubs and camps, have been associated with the development of youth’s science, technology, engineering, and mathematics interests and career aspirations. However, research on ISLEs predominantly focuses on institutional settings such as museums and science centers, which are often discursively inaccessible to youth who identify with minoritized demographic groups. Using latent class analysis, we identify five general profiles (i.e., classes) of childhood participation in ISLEs from data reported by a nationally representative sample of college students (N = 15,579). Results show that childhood participation in specific typologies of ISLEs (i.e., setting and activity type) is associated with youth's disciplinary interests at the end of high school. Participation in outdoor activities that invite observation is more often reported by female respondents and is negatively associated with interest in computing and mathematics. Participation in indoor activities that invite object manipulation is more often reported by male respondents and is positively associated with interest in computing and engineering. However, frequent participation in multiple ISLEs is positively associated with interest in “science.” These results elucidate stereotypical discourses that reinforce the exclusion of minoritized students and expose critical areas needing reform.