The longfin mako resembles the shortfin mako, but has larger pectoral fins and larger eyes. The presence of only one lateral keel on the tail and the lack of lateral cusps on the teeth distinguish the makos from the closely related porbeagle sharks of the genus Lamna . The line of demarcation between blue and white on the body is distinct. The underside of the snout and the area around the mouth are white. The latter is important because is helps differentiate the shortfin from the longfin mako, which has a darkly pigmented mouth region.
Color is related to size.
Larger specimens tend to possess darker color that extends onto parts of the body that are white in smaller individuals. The juvenile mako differs in that it has a clear blackish stain on the tip of the snout. The mouth is parabolic, or bowl-shaped, with the first teeth of the lower jaw aligned in a continuous row. They are blade-like without basal cusps or serrations. Teeth of both the upper and lower jaw are roughly uniform in size and shape with the first two teeth on either side of the mandibular symphyses being longer and more slender than the rest.