Volunteerism is a critical pillar of civil society, often conceptualized as a pure expression of altruistic social values. However, the motivations that drive individuals to volunteer are complex and multifaceted. This study investigates the primary motivations for volunteerism among participants in community-based organizations (CBOs) and examines how these motivations correlate with volunteer retention and satisfaction. Utilizing a mixed-methods approach, quantitative data was collected via an online survey (N=207) incorporating the Volunteer Functions Inventory (VFI), and qualitative data was gathered through semi-structured interviews (N=15). Quantitative results revealed that while values (altruism) was a significant motivator (M=4.21, SD=0.72), it was closely rivaled by the understanding motive (desire to learn new skills) (M=4.18, SD=0.68). Qualitative analysis uncovered a synergistic relationship between altruistic and instrumental motives, where personal growth often reinforced commitment to altruistic goals. A significant positive correlation was found between a diversity of motivating factors and long-term retention (r(205) = .45, p < .001). The findings challenge the simplistic altruism-instrumentalism dichotomy, suggesting that effective volunteer management requires recognizing and nurturing this broad motivational spectrum to foster sustainable engagement.