It has a single dark green leaf with a reddish purple base and up to seven greenish to brownish flowers with red lines and a labellum with a reddish purple beard.

Calochilus uliginosus is a terrestrial, perennial, deciduous, herb with an underground tuber and a single dark green, linear to lance-shaped leaf, 100–400 mm (4–20 in) long and 5–12 mm (0.2–0.5 in) wide with a reddish purple base and which is fully developed when the first flower opens.

[2][3][4][5] Calochilus uliginosus was first formally described in 2006 by David Jones and the description was published in Australian Orchid Research from a specimen collected near Albany.

[6] The specific epithet (uliginosus) is derived from a Latin word meaning "marsh" or "swamp",[7] referring to the habitat preference of this species.

[5] The swamp beard orchid grows in dense undergrowth in seasonal swamps between Gingin and Albany in the Jarrah Forest, Swan Coastal Plain and Warren biogeographic regions.