Phlorotannins isolated from brown algae, such as Eisena bicyclis, have positive physiological effects, including anti-cancer, anti-inflammatory, and anti-Alzheimer’s disease. Although phlorotannins have been shown to inhibit tyrosinase, an enzyme essential for melanogenesis, their effect on melanogenesis remains unexplored. Thus, we isolated phlorotannins from E. bicyclis and examined their effects on α-melanocyte-stimulating hormone (α-MSH)-induced melanogenesis in murine B16 melanoma cells. Both fucofuroeckol-A (FF-A) and phlorofucofuroeckol-A (PFF-A) suppressed α-MSH-induced melanogenesis. Neither inhibited human tyrosinase (TYR) activity, but both inhibited tyrosinase-related protein-2 activity. FF-A downregulated the expression of microphthalmia-associated transcription factor and TYR, which subsequently suppressed melanin production. These results suggest that phlorotannins could be beneficial as melanin control drugs for hyperpigmentation disorders.