Urban mobility systems are increasingly expected to operate under uncertainty, disruption, and rapid socio-technical transformation. Traditional planning approaches, often technocratic and efficiency-driven, are insufficient to ensure long-term sustainability, resilience, and legitimacy. Drawing on empirical evidence from Social Acceptability Workshops conducted in Bratislava, Larissa, and Thessaloniki as part of the AntifragiCity project, this paper examines how deliberative engagement contributes to the co-creation of antifragile urban mobility systems. The findings show that deliberation enhances understanding of trade-offs, broadens perspectives, and reveals the discursive dynamics shaping citizens’ reasoning. Participants prioritized structural, system-level improvements, accepting restrictive measures only when embedded in fair, transparent, and equitable frameworks. The results indicate that deliberative co-creation supports both social acceptability and antifragility by enabling collective learning, surfacing conflicting values, and strengthening adaptive capacity in mobility governance.