This study compared the dynamic mechanical and thermal properties of biocomposites reinforced with algae fiber; polypropylene (PP) and poly(lactic acid) (PLA) biocomposites. The biocomposites are manufactured with a bleached red algae fiber (BRAF) loading ranging from 30 to 60 wt%. The thermal properties of BRAF, PLA and PP were determined by DSC and TGA. The dynamic mechanical and thermomechanical properties of the PLA matrix and biocomposites were analyzed by DMA and TMA. The dynamic mechanical and thermomechanical properties of both BRAF/PLA and BRAF/PP biocomposites show improvement with increasing BRAF loading. The fibers were well bonded with the PLA matrix, indicating strong adhesion, as observed by SEM observations of the fractured surface. In addition, greater improvement in the storage modulus was achieved with the BRAF/PLA biocomposites than with the BRAF/PP biocomposites. Therefore, BRAF/PLA biocomposites can be used as an alternative completely biodegradable biocomposite to BRAF/PP biocomposites.