Males appear to reach maturity at about 2 meters, while females mature at a somewhat larger size. One study showed males attaining sexual maturity at 195 cm; females at 280 cm. Size at birth is about 70 cm, and litter size varies from about 4 to 16. Young makos grow rapidly in length and weight.
Gubanov's studies on the shortfin mako suggest that it exhibits placental viviparity, but in other studies no placentae or umbilical cords were found. In some studies there were quantities of yolk found in the embryos' stomachs, suggesting that the embryos are oviphagous.