The anti-corrosion efficacies of two polymeric molecules, polyvinyl alcohol (PVA) and alginic acid (AA), on the corrosion of SABIC type-X60 carbon steel (CSX60) in 1.0 M HCl solutions were investigated. Chemical and electrochemical techniques, such as weight loss analysis, galvanostatic polarization, potentiodynamic anodic polarization (PDAP), and electrochemical impedance spectroscopy were employed. The results of these experiments revealed that the anti-corrosion activities increased with decreasing temperatures and increasing concentrations of PVA and AA. The surface morphologies of the investigated steel surfaces were analyzed via scanning electron microscopy. The anti-corrosive strengths of the polymeric molecules with respect to the general and pitting corrosion behavior were demonstrated via the formation of adsorbent films that isolated the CSX60 surface from the aggressive acidic solutions. The inhibitor adsorption followed the Langmuir isotherm model. A few thermodynamic activation parameters were also calculated and discussed. PVA and AA were found to retard the pitting corrosion of CSX60 based on the shift of pitting potential to a nobler direction in the PDAP profiles.