One new sand lance, Ammodytoides idai Randall & Earle, n. sp., is described from 10 specimens, 67.2–121.3 mm standard length, collected on sand substratum in the depth range of 8–25 m from the D'Entrecasteaux Islands, Papua New Guinea. It is characterized by 44–46 dorsal rays, 21–22 anal rays, 14–16 pectoral rays, 103–107 pored lateral-line scales, two or three small scales dorsally on the opercle, 5–6 21–23 gill rakers, 55–58 vertebrae; a series of black spots distally in the dorsal fin, and a blackish posterior border on the caudal fin (at least on adult males), broadening toward lobe tips. A second similar species, A. praematura Randall & Earle, n. sp., is described from a single 61 mm specimen from the Chagos Archipelago, differing in having 48 dorsal rays, 24 anal rays, black dots in the dorsal and anal fins, no submarginal black spots in the dorsal fin, and a curved blackish bar across each lobe of the caudal fin. A key is provided for the eight known species of Ammodytoides.