Reefine is a modular, biomimetic reef unit designed to improve coral restoration success. Using minimal surface geometry, it enhances water flow, stability, and sediment resistance. Made from recycled oyster shells and a zero-cement binder, the material supports coral calcification and marine attachment. Unlike 3D-printed structures, Reefine is locally cast using simple moulds, enabling low-cost, low-carbon production. This approach empowers coastal communities with an accessible, ecologically sound tool for rebuilding reef habitats and restoring marine biodiversity