Bluefin tuna inhabit the open waters of the North Atlantic Ocean, where they roam across immense distances in search of food and suitable spawning conditions. Unlike coastal fish, they spend much of their lives far offshore, often diving hundreds of feet beneath the surface while moving between productive feeding grounds.

In the western Atlantic, important feeding areas include the waters off New England, Atlantic Canada, and the Gulf of Maine. In the eastern Atlantic, bluefin tuna are commonly found from the waters around Portugal and Spain northward into the Norwegian Sea. Seasonal concentrations often develop wherever large schools of baitfish gather.

Spawning occurs primarily in two regions: the Gulf of Mexico and the Mediterranean Sea. Juveniles spend their early years growing in warmer waters before joining larger migratory populations that traverse the Atlantic throughout their lives.