This article describes and explains shifts in participation among eight mathematically successful Latin@ undergraduate students who were enrolled in a culturally diverse calculus I workshop that was part of a university-based Emerging Scholars program. Two questions are explored: (a) How do students explain success-oriented shifts in participation that occurred over time in the workshop setting? and (b) How were these success-oriented shifts related to students' evolving mathematical and racial identities? Drawing on Wenger's (1998) social ecology of identity framework, the analysis shows that participants constructed strengthened identities of participation over time through three modes of belonging (engagement, imagination, and alignment) within two dimensions (identification and negotiability). Given the predominantly White university context, Latin@ Critical Theory was used to help uncover how strengthened participation was related to what it meant for participants to be Latin@. Findings also support intentional collaborative learning environments as one way to foster mathematics success and positive identity development among Latin@ students.