The ongoing transition from diesel to hydrogen as an automotive fuel raises critical questions regarding the susceptibility of aluminium engine components to hydrogen-induced degradation. This thesis presents the electrochemical investigation of hydrogen permeation behaviour across five aluminium alloy specimens used in hydrogen-fuelled internal combustion engine systems: three reference wrought and cast alloys – Al-4xx.x, Al-5xxx and Al-6xxx and two commercially sourced automotive engine components, an engine head (Al–319 casting alloy) and an inlet manifold (A380 die-cast alloy). Hydrogen permeation experiments were conducted using the Devanathan–Stachurski (DS) electrochemical cell in accordance with the frameworks established by ISO 17081 and ASTM G148. Specimens were prepared with platinum sputter coatings (30–50 nm) on the oxidation side to ensure catalytic surface activity.