Thelymitra uliginosa is a tuberous, perennial herb with a dark green leaf which is egg-shaped near the purplish base, then suddenly narrows to a linear, curved or spirally twisted upper part.

[2][3][4][5] Thelymitra uliginosa was first formally described in 2009 by Jeff Jeanes from a specimen collected in the Walpole-Nornalup National Park and the description was published in Muelleria.

[5][6] The specific epithet (uliginosa) is a Latin word meaning "full of moisture", "wet" or "marshy"[7] referring to the habitat preference of this species.

[5] Southern curly locks grows in shrubby vegetation in and around winter-wet areas and swamps.

[2][3][4][8] Thelymitra uliginosa is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.