This species is strictly marine, generally feeding on inshore waters. Its diet is comprised mainly of flying-fish and squid, but also some halfbeak (Hemiramphu), mullet (Mugil) and anchovy (Engraulis). Prey is usually caught by plunge-diving and it can also snatch prey off the surface of water. Kleptoparasitism has been observed, mostly by females. Breeding is seasonal in some areas, but elsewhere it breeds opportunistically or more or less continuously. Nests are built on the ground in the midst of vegetation on rocky islands or coral atolls. Individuals form colonies that are usually smaller than those of other Sula species (del Hoyo et al. 1992).

The Brown Booby can be found throughout the pantropical oceans with few exceptions. Breeding sites include the Carribean, the Atlantic coasts of Brazil and Africa, oceanic islands off Madagascar, the Red Sea, northern Australia, many oceanic islands in the western and central Pacific, as well as off the coast of Mexico and Peru.