Cold sintering is a technique that can be used to densify metastable, temperature-sensitive materials, thereby bridging the gap in sintering ceramics and polymers. In this investigation, we evaluated the potential of cold sintering for densifying amorphous calcium phosphate (ACP) and low-crystalline apatite (LowAp)-biopolymer composites. Both ACP and LowAp were synthesized through a reprecipitation process utilizing CaO (or mussel shells as a natural calcium source), H3PO4, HCl, and NaOH. Biopolymers such as silk fibroin, polylactic acid, chitosan or polycaprolactone were added to the calcium phosphate synthesis solution or mixed with the synthesized CaP in an appropriate solvent before evaporating the solvent, thus producing the biocomposite with a biopolymer content range between 2-20 wt%. The resultant CaP and CaP-biopolymer powder were then sintered uniaxially at room temperature at a pressure range of 500-1500 MPa. X-ray diffraction and Fourier transform infrared spectroscopy confirmed that ACP and LowAp phases were retained upon sintering. The relative density of the ACP and LowAp samples increased with increasing compaction pressure, reaching >90 % when sintered at 1250-1500 MPa. Vickers hardness of the ACP and LowAp samples compacted at 1500 MPa exceeded 1.9 GPa. Most of the CaP-biopolymer composite samples compacted at 1000 MPa showed relative densities over 85 %. For the CaP-biopolymer composite samples, Vickers hardness decreased with increasing biopolymer content. Furthermore, biomineralization tests indicate a rapid formation of an apatite layer on the surface of the ACP-biopolymer samples.