Salicornia herbacea (SH) is a halophyte that grows in the salt marshes along the coastline of South Korea, and is known to have antioxidative activity. In this study, the antioxidative and skin-whitening effects of SH aqueous extract were investigated in human dermal fibroblasts (HDFs) and B16 melanoma cells. The water extract of SH had potent antioxidative capacity and protected HDFs from tert-butyl hydroperoxide (tbOOH)-induced oxidative stress in a dose-dependent manner. In a cell cycle analysis, pretreatment with SH reversed the apoptotic cell death induced by tbOOH in HDFs. Additionally, the incubation of SH in mushroom tyrosinase inhibited the oxidation of l-dopa to o-dopaquinone, which implies that SH is a potent tyrosinase inhibitor. An SH treatment to B16 melanoma cells decreased the synthesis of melanin and inhibited tyrosinase activity. These results collectively indicate that SH had antioxidative and whitening effects on skin and would be a good candidate for skin rejuvenating agent.