Circumglobal in temperate and tropical waters. Western Atlantic: Newfoundland, Canada to Argentina. Central Atlantic. Eastern Atlantic: Norway to South Africa, including the Mediterranean. Indo-West Pacific: East Africa to Indonesia, Japan, Australia, New Caledonia, and New Zealand. Eastern Pacific: Gulf of Alaska to Chile. Probably the widest ranging chondrichthyian. Highly migratory species, Annex I of the 1982 Convention on the Law of the Sea.

A slim, graceful blue shark with a long, conical snout, large eyes, and curved triangular upper teeth with saw edges; pectorals long and narrow; no interdorsal ridge. Dark blue dorsally, bright blue on the sides, white ventrally. Tips of pectoral fins and anal fin dusky.

Oceanic, but may be found close inshore where the continental shelf is narrow.