Hammerhead sharks live in warm coastal and tropical waters across every major ocean, generally between 40°N and 35°S latitude. That band stretches from the Carolinas and Southern California down through the Caribbean, across the coasts of Africa, throughout the Indian Ocean, and into the western Pacific. But the specific answer depends on which hammerhead you’re asking about, since the family includes around nine species with overlapping but distinct ranges and habitat preferences.
Global Range by Ocean
The great hammerhead, the largest of the group, is found throughout warm waters worldwide. In the western Atlantic, its range runs from North Carolina south to Uruguay, including the Gulf of Mexico and Caribbean. In the eastern Atlantic, it spans from Morocco to Senegal and enters the Mediterranean Sea. It also occupies the Indian Ocean and Indo-Pacific, from Japan’s Ryukyu Islands down to New Caledonia and French Polynesia, and in the eastern Pacific from Baja California south to Peru.
The scalloped hammerhead covers a similarly broad range but pushes slightly into cooler temperate zones. It reaches as far north as New Jersey along the U.S. Atlantic coast and extends to Brazil. In the eastern Atlantic, it ranges from the Mediterranean to Namibia, farther south than the great hammerhead. Scalloped hammerheads also inhabit the Red Sea, waters off South Africa, and stretch across the Indo-Pacific from Japan and the Philippines to Australia. In the eastern Pacific, they’re found from Southern California through the Gulf of California to Ecuador, plus around Hawaii and Tahiti.
Coastal Waters, Reefs, and Open Ocean
Most hammerhead species are primarily coastal sharks. They favor continental shelves, coral reefs, and the edges of drop-offs rather than the deep open ocean. Scalloped hammerheads in particular stick close to coastlines and island margins, where they hunt along reef systems and near underwater seamounts. Great hammerheads also prefer shallow coastal areas but will cross open water between islands and along continental margins during migrations.
Despite their coastal tendencies, hammerheads are capable of remarkable depth. Scalloped hammerheads dive repeatedly from warm surface waters around 26°C down to depths exceeding 800 meters, where temperatures plunge to about 5°C. A 2023 study published in Science revealed how they pull this off: they close their gill slits during deep dives to trap body heat, essentially holding their breath to stay warm in frigid water. These deep dives likely target prey like squid and deep-water fish concentrated at those depths, but the sharks return to warm surface waters between plunges.
The Bonnethead’s Seagrass Habitat
The bonnethead, the smallest hammerhead species, occupies a niche unlike any other shark. With an estimated 4.9 million individuals along the Atlantic and Gulf of Mexico coasts of the U.S. alone, bonnetheads are one of the most abundant sharks in shallow seagrass meadows and soft-bottom coastal habitats. They show short-term residency in core areas within seagrass beds, then shift locations within a larger home range.
What makes their habitat choice especially unusual is that bonnetheads actually eat the seagrass around them. Seagrass can make up over 60% of their gut contents by mass. For years, scientists assumed this was accidental ingestion while hunting crabs and shrimp. But research from the Proceedings of the Royal Society B confirmed that bonnetheads can digest and extract nutrients from seagrass, making them the only known shark with a partly omnivorous diet. This means they play an active role in seagrass ecosystem health, potentially transporting nutrients between habitat patches as they move.
Major Aggregation Hotspots
Hammerheads are famous for forming enormous schools, sometimes numbering in the hundreds, at specific locations around the world. The most celebrated gathering points sit in the eastern Pacific. Cocos Island, about 550 kilometers off the coast of Costa Rica, draws massive schools of scalloped hammerheads to its underwater pinnacles and cleaning stations, where small fish pick parasites off the sharks. Divers encounter them at sites like Bajo Alcyone, Dirty Rock, and around the island of Manuelita, where hammerheads cruise at depths of 18 to 30 meters and deeper.
The Galápagos Islands host similarly large aggregations, particularly around the northern islands of Wolf and Darwin. Other well-known hotspots include Malpelo Island off Colombia, the Red Sea’s Brothers Islands and Daedalus Reef, and Layang-Layang atoll off Malaysian Borneo. These sites share common features: strong currents that bring nutrient-rich water, cleaning stations where reef fish service the sharks, and underwater topography like seamounts and walls that concentrate prey.
Migration and Seasonal Movement
Hammerheads don’t stay in one place year-round. Great hammerheads in the southeastern United States exhibit what scientists call partial migration: some individuals make consistent, repeatable round-trip journeys between the Florida Keys and points farther north along the Atlantic coast or into the Gulf of Mexico. A telemetry study tracking 15 mature great hammerheads from 2019 to 2022 found that individual sharks showed a preference for one ocean basin or the other, repeatedly choosing either the Atlantic or Gulf of Mexico route.
Even sharks that stayed in the Florida Keys shifted their behavior with the seasons. During spring and summer, they concentrated in inshore channels. From summer through winter, they moved to offshore artificial reefs and natural reef tracts. These shifts appear to follow food. The sharks’ core use areas often overlapped with known spawning aggregation sites for reef fish, suggesting they time their movements to intercept predictable prey concentrations.
In broader terms, hammerheads across species tend to move toward higher latitudes in summer as water temperatures rise, then retreat toward the equator or into deeper water during cooler months. This is why sightings along the U.S. East Coast peak in warm months and drop off sharply by late fall.
Nursery Areas Along Tropical Coasts
Female hammerheads give birth in shallow coastal waters that serve as nurseries for pups. These areas offer two advantages: abundant small prey for young sharks and reduced exposure to large predators that patrol deeper water. Along the eastern tropical Pacific, scalloped hammerhead nurseries have been identified across the Pacific coasts of Central and South America, including mainland coasts of Panama and Ecuador. Newborns have also turned up in shallow bays around the Galápagos Islands and Cocos Island, meaning even remote oceanic islands can function as nursery habitat.
In the western Atlantic, shallow bays along Florida, the Gulf of Mexico coast, and the Caribbean serve similar nursery roles. Young hammerheads typically remain in these sheltered waters for months to years before gradually expanding their range into deeper, more exposed habitats.
Shrinking Range and Conservation Status
The great hammerhead is listed as Endangered on the IUCN Red List, and the scalloped hammerhead carries the same designation. Their coastal habits make them especially vulnerable to fishing pressure, both as targeted catch and as bycatch in nets and longlines. Population declines have been particularly severe in parts of the eastern Atlantic, where fishing efforts are unmanaged and unmonitored.
Their tendency to gather in large, predictable schools at known locations, the very behavior that makes them spectacular to encounter, also makes them easy to exploit. A single net set at an aggregation site can remove dozens of individuals at once. While hammerheads still occupy most of their historical range, local populations have been depleted or functionally eliminated in areas with heavy fishing pressure, particularly in Southeast Asia and West Africa.