Despite its small size, in the show ring the Cardigan Welsh Corgi must be able to demonstrate great power. Indeed, the dog's heritage demands that he possess great speed and endurance, while all the while retaining a handsome appearance. He must be sturdy, but not in a bulky way and must give the air of an intelligent dog ready for anything. Physically, he is much longer than he is tall and is moderately heavy boned. His tail is set low and has a fox-like brush.

There are no stringent requirements when it comes to the size of these dogs as judges are more interested in overall balance. In general, both males and females should measure about 10.5 to 12.5 inches in height, with males weighing about 30 to 38 pounds and females weighing from 25 to 34 pounds. Any deviations from a balanced structure will be considered serious faults and could constitute grounds for disqualification. The head should be refined and should itself also be properly balanced in relationship to the overall structure of the dog. The dog must have a friendly, even gentle, yet alert expression with moderately sized wide set eyes (which can be somewhat large) that have dark rims. Judges will accept blue eyes or different colored eyes only in blue merles; with any other colored dog, they are grounds for disqualification.

The Cardigan's ears must be very prominent; in other words, they must be larger than that dictated by proportion. They must be somewhat round tipped and sturdy and must be held erect when alert. The top of the dog's skull must be somewhat flat and wide, especially in between the ears, with a small depression between the eyes. Cardigans must have flat cheeks and lack prominent cheekbones. The muzzle should be rounded and never blunt and its length should be shorter than the skull's length; judges will also be looking for the muzzle to be tapered, not pointed. The nose should be black; the only exception is for blue merles, where butterfly noses are accepted, though black is still preferred. The lips are not large and they must meet evenly, while the teeth must meet in a scissors bite. While other types of bite will not mean disqualification, they are very heavy faults.

The Cardigan neck should not be throaty, but rather somewhat long and muscular. The shoulders are shaped well and muscular themselves, leading into a level topline. The chest is somewhat broad with a breastbone that is prominent. They have a short yet strong loin that is slightly tucked up and a well defined waist. The tail should never be curled over the back, but rather must be low if the dog is standing, lifted if the dog shows excitement and parallel to the floor if the dog is running. Their elbows should be close together, with slightly curved forearms. Feet should be somewhat large and round shaped; dewclaws are removed. Cardigans have a double coat of medium length, with slightly harsh outer hairs that lie smooth. The actual length of the coat varies, going from short on the head and legs, medium on the body and longer in the rear. The coat can be a variety of colors, though a predominantly white coat is a disqualification.