Coastal giant salamanders are the largest salamanders in Oregon. Terrestrial adults are marbled with tan and brown and are mostly tan on their undersides. Larvae are brown with a large head, frilled gills, and a tail fin. Adults can grow to a total length of 14 inches.
This species lives in dense wet forests near cold and clear streams, lakes, and ponds. Terrestrial adults are rarely seen because they spend most of their time in burrows. Occasionally, during times of heavy rain, adults are active on the forest floor.