<p>Urban planners increasingly recognize the importance of improving access to nature to support human well-being, social inclusion, and urban sustainability. However, assessing accessibility to urban green spaces remains challenging, particularly in rapidly urbanizing cities of the Global South, where mobility constraints and socio-spatial inequalities shape who can effectively benefit from these spaces. Urban wetlands, despite providing multiple ecosystem services, are rarely incorporated into formal green infrastructure networks and are often excluded from accessibility assessments. This study examines how integrating urban wetlands as Nature-Based Solutions (NbS) modifies patterns of access to nature in Concepción, Chile. We combine land-use data on parks and wetlands with accessibility measures and origin–destination travel survey data to model walking accessibility under two scenarios: green spaces excluding wetlands and green spaces including wetlands. A Random Forest model is applied to capture heterogeneity across socio-demographic profiles, including age, gender, employment status, and driver’s license ownership. Results show that incorporating urban wetlands significantly increases the accessible surface of green space across the city, with particularly strong gains for groups with limited mobility options, such as women, older adults, unemployed residents, and individuals without access to private vehicles. In peripheral and underserved areas, wetlands partially compensate for deficits in formal park provision, reducing accessibility gaps. These findings provide empirical evidence that urban wetlands function as grounded NbS by redistributing access to nature and underscore the importance of formally integrating wetlands into urban planning instruments to promote more inclusive and resilient cities.</p>