The 15.5–16.5 cm long Tuamotu sandpiper is a small, short-winged, mottled brown bird with more or less barred underparts. Its short sharp beak is more like that of an insectivorous passerine than a wader. There are two colour morphs which intergrade. Pale birds are medium brown above and white below, with light barring or spotting on the breast and whitish streaking on the head. The bold supercilium and the chin are also white. The rectrices are brown with white tips and white triangular markings on the outer webs. Dark phase birds replace medium with darker brown and white with light buff or tawny white. The flanks are brown, and the entire underparts are heavily barred that colour.