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A marine red alga, <i>Symphyocladia latiuscula</i> (Harvey) Yamada (Rhodomelaceae), is a rich source of bromophenols with a wide array of biological activities. This study investigates the anti-tyrosinase activity of the alga. Moderate activity was demonstrated by the methanol extract of <i>S. latiuscula</i>, and subsequent column chromatography identified three bromophenols: 2,3,6-tribromo-4,5-dihydroxybenzyl methyl alcohol (<b>1</b>), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (<b>2</b>), and bis-(2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether) (<b>3</b>). Bromophenols <b>1</b> and <b>3</b> exhibited potent competitive tyrosinase inhibitory activity against <span style="font-variant: small-caps;">l</span>-tyrosine substrates, with IC₅₀ values of 10.78 &#177; 0.19 and 2.92 &#177; 0.04 &#956;M, respectively. Against substrate <span style="font-variant: small-caps;">l</span>-3,4-dihydroxyphenylalanine (<span style="font-variant: small-caps;">l</span>-DOPA), compounds <b>1</b> and <b>3</b> demonstrated moderate activity, while <b>2</b> showed no observable effect. The experimental data were verified by a molecular docking study that found catalytic hydrogen and halogen interactions were responsible for the activity. In addition, compounds <b>1</b> and <b>3</b> exhibited dose-dependent inhibitory effects in melanin and intracellular tyrosinase levels in &#945;-melanocyte-stimulating hormone (&#945;-MSH)-induced B16F10 melanoma cells. Compounds <b>3</b> and <b>1</b> were the most effective tyrosinase inhibitors. In addition, increasing the bromine group number increased the mushroom tyrosinase inhibitory activity.