Bone scaffold is a three-dimensional structure composed of materials that could enhance bone regeneration. Bone scaffolds were prepared using freeze-drying by varying the cockle shell powder concentration where sodium alginate acted as matrix. The scaffolds were then characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, texture analyzer, and liquid displacement method. The bioactivity of the scaffolds was evaluated by immersion into a simulated body fluid solution. Cockle shell powder concentrations affected the bone scaffold characteristics. The increment of the powder concentrations improved the physicochemical properties and bioactivity of the scaffolds.