Although calmer than most terriers, the Welsh Terrier is still very active both inside and out. They are playful, mischievous, independent, and headstrong with great stamina, in short, very much a terrier. They will gnaw on a chew bone while you watch TV or work online but if not provided with activities, they will create them and it may not be what you would prefer. Exercise is important to the breed. They were bred to run and hunt. They need either a long walk or a vigorous play session every day. Access to a securely fenced yard also gives them a chance to exercise and explore. But make sure the fence is at least six feet tall. They also like to dig, so supervision is important for the yard proud. The Welsh Terrier is more accepting than most terriers of poor treatment from children, especially older generally well-behaved children. In fact, they seem to have a small preference for children over other members of the family. Welsh Terriers are predictably wary of strangers, but when combined with their quick bark, this makes them outstanding watchdogs. And with their terrier feistiness, they can be depended on as an outstanding guardian too. They are more accepting of other dogs than many terriers but will not back down if challenged. But owners with other pets beware- they will instinctively stalk and kill small animals, including cats. They can also be possessive of food or toys.

The strong agile Welsh Terrier is a medium-sized, long-legged dog about 15 inches tall and weighing between 20 and 21 pounds. They look similar to the larger Airedale Terrier. Puppies are born with entirely black coats. Their coats then take a year to lighten to tan on the legs and head. Their coat is wiry with a soft undercoat. Although they shed very little, they need to be brushed regularly to keep their coat clean. They do equally well in both the heat and cold.

Welsh Terriers need early and extra socialization to make sure their wariness does not become timidity and to try and reduce their animal aggressive behavior. The breed needs consistent training. With a curious, easily distracted and an independent nature with little or no desire to please anyone but themselves, they are not the easiest to train. Successful training needs to be fun and in short segments. They are best with experienced dog owners.