Snout to vent length 6-9 cm, females larger than males. Dorsal colour of adults ranges from reddish-brown to tan or olive with irregular-shaped black spots with light centers. An extensive, light-coloured stripe down extends along the upper lip to the shoulder. Light brown to orange “dorsolateral” folds extend from behind the eyes to the middle of back. Hind legs have black, mottled striping or blotching. Ventral colouration ranges from cream on the lower jaw transitioning to a rust orange colour on the chest, belly, upper and lower legs all the way to tips of the toes. Some individuals have heavy olive mottling throughout the ventral areas with only small amounts of rust colouration on the ventral area of each leg. No mottling is found in the groin areas. Webbing on the hind feet is extensive, extending to almost the tip of each toe. Unlike other members of its genus, Oregon Spotted Frog have relatively short hind legs. Males develop a “nuptial pad” on each thumb to assist in gripping females (“amplexus”) during breeding. The snout is pointed and eyes are turned upward laterally. Juveniles are olive-green or light brown and lack the bright ventral colouration, large spots and blotches on the hind legs. The olive-brown tadpoles have a long tail, about twice the length of the body, with a colourless tailfin containing scattered flecks. The belly is white or slate in colour and small raised bumps occur on the side.