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Discover Monk Seals — and So Much More — in Kauai and Ni’ihau

Fathom Five Divers can show you all the wonders of this magnificent marine ecosystem in Hawaii, including monk seals, sharks and rays, octopus and endemic fish.
By Patricia Wuest | Updated On June 24, 2024
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Discover Monk Seals — and So Much More — in Kauai and Ni’ihau

Scuba divers with coral and schools of fish in Hawaii.

Fathom Five Divers has been taking divers to the best sites in Kauai and Ni’ihau islands for more than 40 years.

Fathom Five Divers

Fathom Five Divers, which has been taking scuba divers to the best sites in Hawaii’s Kauai and Ni’ihau islands for more than 40 years, is passionate about underwater adventure, marine life education and ocean conservation. Guests can make two- or three-tank boat dives to volcanic pinnacles, ledges, arches and caverns in Kauai — Hawaii’s Garden Island — and Ni’ihau — the state’s mythical Forbidden Isle. Fathom Five takes out groups of no more than six divers on custom-built dive boats to sites such as Tunnels Beach on Kauai’s dramatic North Shore to the remote adventure dives found off Ni’ihau, as well as to Koloa Landing shore dives on Kauai’s beautiful South Shore.

Divers have encounters with monk seals, whitetip reef sharks, eagle rays, octopus and endemic fish found nowhere else on Earth. It would take more than a single article to describe all the marine life a diver will encounter in Kauai, but here’s a sample of some Fathom Five favorites.

Monk Seals (Monachus schauinslandi)

Ni’ihau is privately owned and remote, so booking a trip to this captivating place is truly unique. Its crystal-clear waters are pristine and teeming with marine life. “On Ni'ihau, we generally see monk seals on every dive,” says Jeannette Auber, the owner of Fathom Five. The sites here include a number of stunning formations, including the legendary Ni’ihau Arches.

Green Sea Turtles (Chelonia mydas)

“I will never guarantee any animal to our divers,” says Jeannette. “The minute you guarantee it, you’re not going to see it. But Sheraton Caverns is one of those sites that if you’re not seeing green sea turtles, there’s something wrong that day. We also usually see them on our shore dives at Koloa Landing.”

Green sea turtle in the ocean in Kauai.

Sheraton Caverns is a popular site that is known for green sea turtles.

Fathom Five Divers

Day Octopus (Octopus cyanea)

The day octopus is the octopus most commonly spotted by divers. Well, maybe not always spotted. “They are at many sites,” says Jeannette, “but often, you don't get to see them because they see you first, and they change their color or texture or slide down under a rock. They are geniuses at camouflage.”

Spotted Eagle Rays (Aetobatus narinari)

“Eagle rays can be treat at many sites, including the shore dive at Koloa Landing and the boat dive at Turtle Bluff,” says Jeannette. Encountering these graceful rays underwater is a mesmerizing experience for divers.

An eagle ray swimming in the ocean.

Spotted Eagle Rays are a treat at many sites including Koloa Landing and Turtle Bluff.

Fathom Five Divers

Whitetip Reef Sharks (Triaenodon obesus)

“We mostly encounter whitetip reef sharks, though we’ve sighted some sandbar sharks and gray reef sharks,” Jeannette says. The whitetip reef is the one most commonly encountered by divers because they are the only shark in these waters that can rest for long periods of time. It’s not unusual to find them under ledges or in caves.

A group of scuba divers swimming near a shark.

The whitetip reef is the one most commonly encountered by divers because they are the only shark in these waters that can rest for long periods of time.

Fathom Dive Divers

Endemic Species

“Twenty-five percent of our fish here are endemics and found nowhere else,” says Jeannette. The Fathom Five team’s commitment to educating their guests about fish behavior is very apparent when talking about the endemics.

A good example of this is something local divers have recognized about raccoon butterflyfish (Chaetodon lunula) and the Hawaiian sergeant major (Abudefduf abdominalis).

“We’ve noticed that schools of raccoon butterflyfish will follow us on the reef,” she says. “They’ve learned that if they follow divers who come near to the purple egg nests of sergeant majors, the sergeant majors will charge the divers to keep them away from the eggs, and then the butterflyfish take the opportunity and dart in to eat the eggs. This is a learned behavior that is fairly recent.”

Time to Visit!

The Fathom Five team can’t wait to show you the underwater beauty and amazing marine life found off Kauai and Ni’ihau. They can’t always guarantee a specific animal will show up on a dive, but they are certain that you’ll find the diving transformative. Jeannette made Kauai her home 6 months after her first visit in July 1990. “It was all because of my love for diving, and I still have a tremendous love of it,” she says. “When I first tried scuba, I came up a changed person. We love bringing that joy to our divers and students.”