Background: Authentic research experiences and mentoring have positive impacts on fostering STEM engagement among youth from backgrounds underrepresented in STEM. Programs applying an experiential learning approach often incorporate one or both of these elements, however, there is little research on how these factors impact youth’s STEM engagement during the high school to college transition. Purpose: Using a longitudinal design, this study explored the impact of a hands-on field research experience and mentoring as unique factors impacting STEM-related outcomes among underrepresented youth