They weigh from 800-1000 pounds and have been bred to carry adults. The horse should be somewhat rectangular and well-proportioned. The head must be clean cut and expressive, the neck supple and well set, so that the horse carries itself well-balanced when ridden. The shoulder should be comparatively long and well angled, the back flexible, and the croup sloping, wide and well muscled. The horse must give an impression of courage and power, with a proud and attentive expression, especially when ridden.
Icelandic horses are slow to mature, and are known for their longevity and stamina.
They should not be ridden until the age of 4 years. Their period of greatest strength is from 8 to 18 years, and it is not unusual to ride them until the age of 30. To preserve their natural spirit and vigor, it is best to raise the foals free on pasture and rough ground. All colors and markings are allowed, some of which include chestnut, bay, black, palomino, buckskin, gray and pinto. Breeding is carefully controlled by a breed association in Iceland, and all stallions and mares used pass special tests for conformation, character, temperament, and proficiency in their five natural gaits - walk, trot, canter, pace and tolt.