Evaluation of Green Infrastructure Implementation in Nigerian New Town Developments: Evidence from Eko Atlantic City

New town development projects in coastal Nigeria present opportunities to apply green infrastructure principles from the design stage, yet the gap between environmental commitments in development planning documents and ground-level implementation has not been systematically examined. This study evaluates green infrastructure implementation in Eko Atlantic City, Lagos, a large-scale land reclamation and new city development on Victoria Island's coastline, using a green infrastructure audit framework. The framework assesses implementation across five dimensions: coastal protection and resilience infrastructure, water management, urban green spaces, building-level sustainability features, and ecological corridor provision. Document analysis of environmental impact assessment reports, urban design standards, and investor materials was triangulated with physical field assessment and structured interviews with 15 key informants including project management representatives, environmental consultants, and Lagos State Urban and Regional Planning Authority officials. Findings indicate strong implementation of coastal protection infrastructure, including the sea wall system and beach recharge programme, representing the green infrastructure dimension most directly protecting project economic value. However, urban green space provision falls below the planning document commitment by 22 percent, green building standards are applied inconsistently across individual parcels, and ecological corridor connectivity is inadequate. The study recommends mandatory pre-occupancy green infrastructure compliance audits, integration of green building certification requirements into the development control system, and transparent public reporting on environmental performance against committed indicators. Keywords: green infrastructure, new town development, Eko Atlantic City, coastal resilience, urban sustainability.