This species is a simple, solitary ascidian, with a tough outer covering or tunic. The body is ovoid, without a stalk, and measures 5-7 cm in total length. The oral and atrial siphons are positioned anteriorly, and the short tips are ringed in alternating light and dark stripes. When closed, the tips of the siphons come together to form a puckered cross. The tunic is opaque, thick, and leathery, with distinct warts and longitudinal pleats. Overall colour ranges from tannish to grey.
In the Northeast Pacific, Styela plicata is most similar to to other styelid tunicates, including S. gibbsii (Stimpson, 1864), S. montereyensis (Dall, 1872), S. truncata Ritter, 1901, and two other non-native species found in the region, S. canopus (Savignyi, 1816) and S. clava Herdman, 1881.
Styela plicata has been introduced to the Northeast Pacific, with confirmed records in southern California. In addition, this species has been reported from multiple locations around the world, including the Atlantic coast of the United States, the Caribbean, Brazil, the Mediterranean, Senegal, South Africa, Somalia, China, Japan, Australia, and New Zealand (de Barros et al. 2009). Its native distribution remains unknown.