This quantitative study aimed to understand processes germane to Indigenous graduate students' transcultural socialization in Science, Engineering, Technology, and Math fields (STEM). We theorized that transculturation and "wayfinding" are complementary socialization processes to promote healthy socialization of Indigenous graduate students in STEM. We hypothesized that socialization components including peer interactions, mentor's cultural support, and university environment fit would facilitate academic confidence and cultural congruity. We conducted an exploratory study using a sample of 44 Indigenous STEM graduate students from 12 American public research universities. Our results found elevated levels of cultural congruity among those students who reported more favorable peer interactions, but the simultaneous experiences of mentor's cultural support and university environment fit did not reveal such an influence. Students reported greater levels of academic confidence in the presence of mentor's cultural support and university environment fit but not for peer influence. We situated these findings within prior research and recommendations for programs and practices where universities, peers, and mentors can provide cultural support, inspire academic confidence, and further enhance well-being through honoring the cultural strengths of Indigenous students.