<p>A systematic investigation into the impacts of bromide ion content and direct current density on the passivation and corrosion behavior of CoCrFeMnNi HEA in simulated littoral environment was conducted. Experimental results demonstrate that the elevation of Br⁻ content markedly weakens the pitting resistance of the alloy, which is manifested by the higher metastable pitting density, and the declined pitting potential (<i>E</i>_p) as well as decreased charge transfer resistance (<i>R</i>_ct). Rising i_DC promotes the production of highly defective and thinner passivation film, and destroys the protective performance of the film, thereby resulting in the notably elevated corrosion rate. Besides, synergistic deterioration caused by Br⁻ ion and DC current density induces the generation of multi-sized pits that coalesce into large and deep corrosion pits, thus aggravating the corrosion damage of the HEA. Aggressive ions (H⁺, Br⁻, and Cl⁻) adsorb and penetrate the alloy matrix/film interface, which accelerates the electrochemical dissolution, consequently leading to a remarkable deterioration in the anti-corrosion property of CoCrFeMnNi HEA.</p>