Commercially, polyamide 12 (PA12) is one of the polymers applied as an internal insulation layer in offshore exploitation. The present study aims to produce a hybrid system based on PA12 with 5 wt% of a nanoclay grade (montmorillonite -MMT) and evaluate its effect on the barrier behavior of the PA12 matrix, the exact grade used in the pressure layer of flexible pipe, over carbon steel AISI 1020, metallic alloy responsible for providing the mechanical properties to flexible pipes. The barrier behavior, related to ion and molecule diffusion in synthetic production water, was assessed by Electrochemical Impedance Spectroscopy (EIS) and linear sweep voltammetry (LSV) analysis, which allow for interpreting the carbon steel corrosion mechanisms. One also carried out Fourier transform infrared, X-ray diffraction, and Scanning electron microscopy analyzes. The data showed that the MMT lamellae are well-dispersed in the PA12 matrix. EIS and LSV analysis results showed higher corrosion protection efficiency by the system composed of PA12/MMT once compared to the system without adding the load.