The grapsid crab Metopograpsus oceanicus (Jacquinot, 1852) is recorded from the Hawaiian Islands for the first time; it appears to be established at least in Kāne‘ohe Bay on O‘ahu. I review the ecology of the species in Oceania and argue that it was introduced both to the Hawaiian Islands and Guam, likely by shipping traffic. A brief review of Metopograpsus in the Hawaiian Islands is also presented.