Llewellins are medium-sized gun dogs, typically standing 58 to 69 cm (23 to 27 inches) for males and 56 to 64 cm (22 to 25 inches) for females, with males weighing 23 to 32 kg (50 to 70 pounds) and females 20 to 27 kg (45 to 60 pounds). They generally run smaller and lighter-framed than bench-type English Setters, but because no breed standard exists, size varies noticeably between lines.
The soft, medium-length coat carries silky feathering on the legs, belly, and tail. Llewellin puppies are typically born nearly white, with their "ticking" (spotting) developing as they grow — and the adult patterns span the classic belton range: blue belton, orange belton, lemon belton, chestnut, tri-color, and roan, plus black-and-white and chestnut-and-white variations. The overall picture is a leaner, more workmanlike version of one of the prettiest dogs in the gun dog world.