Tribocorrosion is an important phenomenon encountered in many practical engineering situations, resulting in accelerated materials degradation and serious economic losses. In this work, pin-on-disk friction experiments were carried out in seawater to investigate the dependence of tribocorrosion on time. As rubbing proceeded, the mass loss rate of 304SS decreased, and the dominant wear mechanism changed from abrasion to delamination. In addition, during tribocorrosion, friction-induced -martensite would be transformed at room temperature. The volume fraction of transformed martensite was determined by test time, which played a dual role in accelerating corrosion and reducing wear. Additionally, the synergistic effect between corrosion and wear was analyzed; the main causes of 304SS degradation during tribocorrosion were pure mechanical wear and corrosion accelerated wear.