Hong Kong consumes seafood at a rate three times the global average, importing over 3,000 tonnes of oysters annually. This leads to more than 2,500 tonnes of shell waste each year, about 7,000 kg (up to 350,000 shells) discarded daily. With limited waste management capacity, most of this shell waste ends up in landfills, putting extra pressure on Hong Kong’s three landfill sites, which are expected to reach capacity by the 2030s. We propose turning this food waste into an ecological asset, by collecting post-consumer oyster shells from local restaurants and processing them into materials for 3D printing artificial reefs. The high calcium carbonate content of oyster shells, which closely resembles the mineral composition of natural coral reefs, makes them ideal for creating artificial reef substrates. The 3D-printed reefs are specifically designed to facilitate settlement by coral larvae. This approach opens up new opportunities for coral restoration through sexual reproduction, complementing existing asexual propagation techniques that rely on coral fragments. Overall, by transforming shell waste into a resource for marine restoration, we offer a sustainable pathway for both waste reduction and coral conservation in Hong Kong and beyond.