The present study reports on the development and characterization of Mg-Ta-HA composites through the use of powder metallurgy. The densities and porosities of magnesium composites and pure magnesium are calculated, and the rule-of-mixture method is used to determine the theoretical density of the composites. It is verified that dense pure magnesium and magnesium composites can be produced using powder metallurgy techniques. Examining the composites’ microstructures reveals the uniformity of the grain size as well as the impact of changing the Ta and HA reinforcement. The lack of intermetallic compounds between magnesium and reinforcements is confirmed by X-ray diffraction analysis. Magnesium powders undergo mechanical milling to lower their average particle size, and reinforcement materials are added to further reduce the particle size. The reduction in powder size is attributed to the friction caused by reinforcement materials during the milling process. The densification and porosity of the composites are influenced by the compressibility of the green compacts and the particles’ attachment during sintering. The microstructures exhibit a uniform distribution of Ta and HA particles within the magnesium matrix, and no particle clustering is observed. The addition of HA contributes to the reduction of porosity and defects in the composites.