This article examines the experiences of first-year Latina/o undergraduates at a predominantly white institution. Through a borderlands analysis, the authors explore how these students describe their experiences participating in an ethnic studies course and mentoring Latina/o elementary schoolchildren. The authors find that these experiences served as "sitios y lenguas" (decolonizing spaces and discourses; Perez, 1998) in which the undergraduate students were able to reflect on the ongoing transformation of their social and political identities, revealing the complex and fluid "latinidades" (Latina/o identities; Latina Feminist Group, 2001) that exist among the Latina/o university students. This article explores the physical and metaphorical borders (Anzaldua, 1987) the undergraduates occupy, navigate, and challenge while they work simultaneously as mentors in a mostly Latina/o setting and as college students on a mostly white campus. (Contains 1 table and 7 notes.)