Anoectochilus sandvicensis is a decumbent perennial herb that can reach 10–50 cm in height. It features rhizomes about 0.5–1 cm in diameter, which are slightly enlarged and adventitiously root at the nodes. The leaves are simple and alternate, confined to the ascending portion of the stem. The blades are elliptic to ovate, measuring 4–8(–10) cm long and (1.5–)2–4 cm wide, with the midrib impressed on the upper surface and slightly raised on the lower surface. The leaves have an acuminate apex and an attenuate base. These leaves are dark green on the upper and somewhat paler on the lower surfaces. The margins are entire, and the veins run parallel. Petioles are 1.5–3 cm long, including a sheath that flares to 0.5–1 cm long and is glabrous or sparsely pubescent. There are no stipules. Flowers are found few to numerous in loose spikes 5–15 cm long, varying from glabrous to densely pubescent. Each flower is subtended by a narrowly ovate, channeled, 1–3–nerved bract that is 1.2–2 cm long with entire margins to rarely finely serrulate. The flowers are bisexual (perfect), featuring a dorsal sepal that is pale green to greenish-yellow, ovate, 5–8 mm long, and glabrous or sparsely pubescent. The lateral sepals are partly connate, enclosing the base of the labellum, and are pale green to yellowish green, ovate to oblong-ovate, and 6–8 mm long, glabrous. Lateral petals are appressed to the dorsal sepal, ascending, greenish-yellow, +/- unequally ovate, and 4–6 mm long, glabrous. The labellum is horizontal or slightly ascending, pale to bright yellow, 9–12 mm long, with a base divided into two spurs each containing a single unstalked gland, the middle part of the lip convoluted forming a tube 4–6 mm long, unappendaged or with 0–6 pairs of small teeth along the lateral edge, somewhat fleshy, and the apex expands into a conspicuous transverse, 2-lobed blade 3–5 mm long, apex emarginate. The column is about 2.5 mm long. The fruits are fusiform capsules, 1–1.5 cm long. Seeds are linear, reticulation alveolate, very numerous, extremely minute, translucent, and iridescent, with an embryo visible through the seed coat, measuring 0.8-1.8 mm in length It usually occurs in dense shade on wet, bryophyte-covered ground or the lower parts of tree trunks, rarely epiphytic on tree ferns, in wet forests, at elevations ranging from 275–1,710 m.