Basking sharks are one of the world’s largest and most elusive fish species. But off the Irish coast, these gentle giants swim so close to the shore you can nearly touch them.

Word quickly spreads along the coast of Ireland each year when the giants arrive. Despite visiting their breeding grounds in County Mayo for more than a decade, I had never seen one myself until I was standing at a dizzying height on a wind-whipped hill on Achill Island.

Shielding my eyes from the Sun’s glare, I followed the clear blue water away from Keem Beach and saw two basking sharks lazily cruising just offshore beneath the sweeping cliffs. From the moment I spotted the behemoths swishing through the bay from a distance, I knew I had to see them up close.

Fast-forward a week later and I’m peering over the side of a boat as it putters to a stop. My knuckles grasp the railing, and I steady myself as I lean forward and prepare to come face to fin with one of the world’s largest and most elusive sharks.

Each year from April to early July and then again in August and September, hundreds of endangered basking sharks come to Ireland’s western and south-western coasts to feast on copepods and plankton blooms so large they can be seen by satellites. In fact, the area from Donegal Bay to County Cork is arguably the best place on Earth to see basking sharks, as these temperate-water titans swim so close to the shore in shallow-water bays that you can almost reach out and touch them.

According to Dr Chelsea Gray, a researcher with the Irish Basking Shark Group (ISBG), “basking sharks are global citizens”. But while the animals live in cold waters from Scotland to New Zealand, she notes that “Ireland is really unique in that they come so close to shore”, making it easy to spot them from both the land and sea.

Basking sharks are the second-largest fish in the world and just one of three plankton-eating sharks. A closer relative of great whites than its fellow filter feeder, the whale shark, these slow-moving gentle giants can grow up to 10m (33ft). Their name comes from their propensity to swim along the ocean’s surface to feed on zooplankton, making them appear to bask in the Sun’s rays. As a result, the fish’s local Gaelic name is liamhán gréine, or “sun fish”.

Since Ireland’s shallow coastal shelf attracts zooplankton especially close to its beaches, the island has become the place for travellers seeking a close encounter with the mammoth creatures.

Basking sharks are longtime visitors to Irish waters. During the 1950s and ’60s, Achill Island served as the world’s largest basking shark fishing and processing hub. Their one-tonne livers were harvested for oil and used for everything from cosmetics to commercial lubricants and as a medicinal treatment for healing wounds. Their fins were also highly sought after for shark fin soup.

Beyond Irish waters, Norwegian, Japanese, Canadian and other fishermen also hunted the massive fish extensively. As a result, basking sharks were nearly hunted to extinction across the globe by the late 20th Century.

Today, more than 40 years after the last basking shark was caught off Ireland in 1984, their numbers and sightings are up around Ireland. Globally, it’s a different story, and as recently as 2018, the shark was added to the International Union for Conservation of Nature’s Red List.

Ireland’s breathtaking coastlines and diverse marine life have made it a popular spot for tourism since 1991, when Ireland became Europe’s first recognised whale and dolphin sanctuary. With the steady growth of shark numbers over the last few decades, basking shark tourism has slowly transformed from a niche activity to one of the most memorable experiences visitors can have in Ireland.

Despite the May sunshine, it’s breezy on the water as our group sets out on Blacksod Sea Safari‘s tour boats along the Mullet Peninsula. I scan the waters as we head further from shore. Pods of dolphins leap between the waves. Gannets dive into the sea. Sometimes you can see minke whales, but we didn’t see any on this trip. I’m more keen to spot that rare grey fin, and luck is on my side.

As our guide switches the engine to neutral, it’s up to the sun fish to come to us. We wait, breathlessly hoping the giant will approach the vessel. Then all of a sudden, stark grey against the cerulean waters, there it is, easy to spot as it passes 9m (30ft) from the boat. Its tail swishes back and forth, slowly moving in our direction. Measuring about 7m (23ft), the shark appears utterly uninterested in us. It’s a marvel that a creature can grow to such an immense size while feeding on organisms too small to see. I’ve never seen anything like it.

Since 2022, basking sharks have been listed under the Irish Wildlife Act, and it is the only fish species that is illegal to hunt, harm or disturb their feeding and breeding areas in Irish waters. Scientists and conservationists like the researchers at IBSG are working towards codifying a code of conduct into law to add an additional layer of protection for the sharks.

For tour operators, this means maintaining a distance. The code of conduct states boats should avoid approaching the sharks and switch their engines to neutral when within 50m (164ft) of the animals.

“Our priority is not to interfere too much with the animals. We tend to lie way back and let them come to us. If we can intercept their path at a safe distance, sometimes they come up and have a look, then move on,” says Paddy Byrne, owner and skipper at Sliabh Liag Boat Trips, which offers basking shark excursions around Donegal’s Sliabh Liag Cliffs. “They’re wild animals, and we’re privileged to see them.”

Due to their unpredictable nature, basking shark encounters aren’t a given, but even without spotting one, tours often pass by seals, dolphins, seabirds and the occasional minke whale. For those fortunate enough to see the sharks, the experience often stays with them forever. 

“We saw a baby basking shark before we even left the first bay,” says Isle of Man resident Izzy Sharpe. Growing up, Sharpe could spot the sharks off the coast of her home, but she says her trip with Blasket Islands Eco Marine Tours in County Kerry proved better than she hoped for. “It was on the way back that suddenly hundreds of basking sharks appeared – every direction you looked in you could see them surfacing. It was incredibly special.”

Longtime Achill Island visitor Hazel Keegan recounts how the sharks treated her group to a close-up during their trip. “They ended up just swimming around the boat. We could see the white of the inside of their mouths quite clearly. They constantly kept passing under the boat! Only then did I really understand the length of them.”

Laura Brown had always wanted to see the basking sharks, and brought her family to Achill Island in the hopes of glimpsing one, but to their great disappointment, none appeared during their sea safari. “Our last day was a glorious sunny day, and we decided to take one last trip to Keem Bay. We looked down into the bay and there were around six to eight basking sharks! My son, his friend, and I raced down to get the stand-up paddle board in the water. They swam underneath us and around us. It was truly magical,” she says.  

“We spent the rest of the day at the beach just watching them.”

Seeing the basking shark up close from the boat renewed my appreciation for these glorious creatures’ immense size, power and beauty. I can only hope we’ll meet again here in Ireland.

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