This shark's tail fin has a greatly elongated upper lobe. The thresher grows to be about 16.5 to 20 feet (5 to 6 m) long with a countershaded body, blue above, white underneath. It has small jaws, but can use its tail to corral and even kill fish. Like other mackerel sharks, it has an anal fin, 5 gill slits, 2 dorsal fins, no fin spines, mouth behind the eyes, and no nictitating eyelids. It is a very strong swimmer and can even leap out of the water. It swims from the surface to a depth of about 1,150 feet (350 m).

Thresher sharks are classified as prized gamefish in the United States and South Africa. Common thresher sharks are the target of a popular recreational fishery off Baja, Mexico. Thresher sharks are managed in some areas for their value as both a recreational sport fish and commercial species.