Description and remarks concerning two species from Saint Paul and Amsterdam Islands. The first record of Ovalipes trimaculatus (de Haan, 1833) from Saint Paul Island means a large eastward extension of the previously known distribution of the species (South America, Tristan da Cunha and South Africa). Some pelagic Grapsidae from Amsterdam Island are regarded as conspecific with the specimens of Pachygrapsus sp. recently described from Tristan da Cunha Islands by Holthuis & Sivertsen, and identified as Planes marinus Rathbun, 1914, a species new to the Indian Ocean. Lepas anatifera anatifera is recorded as epizoic on a pereiopod of this latter brachyuran.