Earth’s fiery volcanic past billions of years ago gave rise to some of the planet’s best diving today — including these amazing seamounts.

What is a seamount?

Technically, any underwater peak that rises more than 3,280 feet from the seafloor without breaking the water’s surface. For divers, the term is used more loosely to describe any undersea peak that drops quickly into the deep on all sides.

Daedalus Reef

Red Sea

Like the Sea of Cortez, the Red Sea is a rift zone, this one between the African and Arabian tectonic plates. As these plates drift apart, slowly widening the space between them, they allow volcanic activity to arise from within Earth’s crust, forming islands along the fault. This is how open-ocean seamounts like Daedalus Reef arose in the deep waters of the Red Sea. It was likely a small island that amassed coral around its shores as the top eroded below the waterline. Today, it’s an oasis of coral rising from the depths where divers can drift along seemingly bottomless walls. Pristine technicolor corals stretch their arms into clear blue waters where large pelagics roam. It’s possible to spot anything from manta rays to thresher sharks at this bluewater outpost, but Daedalus is perhaps most renowned for frequent encounters with barrel-chested oceanic whitetips flanked by their entourages of convict-striped pilot fish.

Roca Partida

Socorros

The Revillagigedo Islands, also called the Socorros, are four volcanic islands 240 miles southwest of Cabo San Lucas, Mexico. They’re also a big-animal lover’s dream destination. The region is still volcanically active: San Benedicto had a major eruption in 1952, and an underwater eruption happened in the 1990s. But for divers, some of the best action happens around the seamount Roca Partida. The tip of the underwater peak rises just above the water’s surface, and at recreational diving depths it’s possible to circumnavigate the rock in a single dive. But you’ll never get bored watching the endless parade of pelagic species, including hammerheads, Galapagos sharks, schools of tuna, and pods of bottlenose dolphins. It’s not out of the question to see whale sharks or orcas, and during the winter season, divers may even spot humpback whales cruising around.

Related Reading: Six Unexpected Dive Adventures Around the World

Gordo Banks

Baja, Mexico

The entire Baja Peninsula is geologic history written into the land. Once part of mainland Mexico, it split off as the Pacific and North American plates spread apart along the same tectonic boundary that includes the San Andreas Fault. The resulting rift caused volcanic activity — part of the Ring of Fire that runs around the Pacific — creating a dramatic underwater landscape of canyons and seamounts. Among these are the Gordo Banks, which lie just off the tip of the peninsula. These seamounts rise from thousands of feet to just within recreational diving depths. The shallowest point on the banks is 125 feet, so this is open ocean, bluewater diving for advanced divers — you make a descent, and the seamount slowly becomes visible around 60 feet. Any divers lucky enough to drop in on these deep peaks might find themselves finning alongside schooling hammerheads and congregations of mobula rays, as well as fish such as tuna and marlin.

South Emma Seamount

Papua New Guinea

Sitting within the biodiversity-blessed Coral Triangle and along the Pacific Ring of Fire, Papua New Guinea offers the best of both worlds, with dramatic underwater formations that are blanketed by the world’s greatest biodiversity of coral and marine-life species. And of PNG’s myriad underwater hot spots, the South Emma Seamount, in New Britain Island’s Kimbe Bay, is arguably among the best. This open-ocean seamount is accessible both by day and liveaboard boats from the Walindi Plantation Resort. The top of the seamount reaches about 40 feet deep, where batfish swim in formation. Cruising around the perimeter, divers can find their fill of everything from schooling jacks and reef sharks, to mind-bending critters like the legume-size pygmy seahorses that cling to gorgonians and psychedelic nudibranchs.

Related Reading: 3 Dive Destinations to Help You Fight the Winter Blues

Hin Daeng

Thailand

In the Andaman Sea, accessible by liveaboards and day boats from Phuket, Thailand, the Hin Daeng seamount is visible from the boat, its rocky peak breaking the surface of the water and its base resting about 230 feet down. The name means “red rock,” and it serves as an open-ocean gathering spot for big animals. Jacks and barracuda swirl around the soft-coral-covered walls, where reef fish frolic en masse among sea fans and anemone gardens. Don’t spend all your time looking down at the reef, however, because manta rays and whale sharks frequently swoop in, buzzing the seamount like bomber planes. Hin Daeng also has a sister site, a pinnacle called Hin Muang, known for blankets of purple corals on its walls.

Princess Alice Bank

Azores

The volcanic Azores sit on the Mid-Atlantic Ridge, the longest mountain range in the world, which runs along the seam that separates the North American and Eurasian tectonic plates. These cracks in Earth’s crust are sites of constant volcanic activity as the plates move away from each other, creating cracks in the seafloor where magma pushes up and forms a long line of mountains. A three-hour boat ride from Pico Island takes divers to an underwater mountaintop called the Princess Alice Bank, which rises from 8,000 feet deep to about 100 feet at the shallowest point. Called the “meeting place of the mobula rays,” the Princess Alice Bank is renowned for congregations of Atlantic manta rays, which flock to the banks to feed on the upwellings of nutrients brought by oceanic currents. Divers can also hang midwater to swim in the blue with schooling tuna, marlin, dolphins and sharks.

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