Activated carbon (AC) can be added to a polymer matrix to achieve electrical conductivity, leading to a potential sensor application. In this study, we evaluated the tensile strength of AC when mixed with a polybutylene terephthalate (PBT)/polyamide 6 (PA6) blend. The PBT/PA6/AC composite was prepared by injection molding with 0, 2, 4, 6, 8, and 10% AC. The samples were subjected to a tensile test following the International Organization for Standardization 527 standard. The tensile strengths of the PBT/PA6/2% AC, PBT/PA6/4% AC, PBT/PA6/6% AC, and PBT/PA6/8% AC samples were found to be 45.13, 44.60, 42.48, and 41.82 MPa, respectively. These values are higher than that (40.93 MPa) of the PBT/PA6 blend, which has no AC. Incorporating AC into the PBT/PA6 blend increases the tensile strength. The PBT/PA6/2% AC sample has the highest tensile strength, whereas the PBT/PA6/10% AC sample has a lower tensile strength of 39.79 MPa than the PBT/PA6 blend. All the PBT/PA6/AC samples have tensile moduli higher than that of the PBT/PA6 blend. When adding AC to the PBT/PA6 blend, the microstructure becomes smaller and finer, enhancing cohesion and improving the mechanical properties. A conceivable application area of the approaches analyzed in this work is that the PBT/PA6 blend can be recycled into conductive polymer composites with a small amount of AC.