The increasing global energy demand and rising environmental concerns have necessitated the development of sustainable and eco-friendly materials. Phase Change Materials (PCMs), which stores and releases latent heat during phase transitions, have emerged as efficient solutions for thermal energy management. These materials play a critical role in enhancing energy efficiency, sustainability, and temperature regulation across various applications. Among innovative approaches, sea shell powder has gained attention as a promising and environmentally friendly PCM due to its natural abundance, sustainability, and unique thermal properties. Seashells, is primarily composed of calcium carbonate (CaCO<inf>3</inf>), in the crystalline forms of aragonite or calcite, are aqua-waste and by-products of marine energy storage materials. The intrinsic properties of sea shell powder, such as high thermal conductivity, thermal stability, and recyclability, make it a viable alternative to traditional PCMs. The research evaluates its thermal properties, heat storage, and environmental benefits, highlighting its applicability in construction, energy systems, and temperature regulation technologies. The findings underscore seashell powder’s cost-effectiveness and eco-friendliness, positioning it as a valuable resource for advancing energy-efficient technologies. In conclusion, sea shell powder represents a sustainable and innovative approach to PCM development. By transforming waste material into a resource for thermal energy management, it contributes to a greener and more sustainable future. Further research and development are essential to fully harness its potential in diverse applications. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.