The primary characteristic which distinguishes a suri from a huacaya is the phenotype of its fleece. The suri's fleece falls close to the body, moves freely, and gives the animal a lustrous, flat-sided appearance. The luster found in the suri's fleece is the primary indication of the animal's quality. In addition, the fiber should be fine, and have good handle (a more slippery handle than huacaya) with a well-nourished, almost greasy feel. The locks or ringlets that make up the fleece should be round, form close to the skin, and have uniform twist to the end. Ideally, the style of lock should be uniform from the top knot to the hock; particular attention should be paid to uniformity and independence of lock across the mid side. The legs and underbelly should be well covered.

A more rounded or fluffy appearance can indicate volume rather than density in a suri's fleece which is undesirable. There should be no crimp in the staple, but a low wave is desirable along the length of an individual fiber. Due to the compactness of the fleece, suris often give the appearance of being smaller than the huacaya, but this is an optical illusion.