Beachgoers in Keem Bay off Achill Island were surprised last week when they caught a glimpse of two fins in the water.
Two basking sharks swam close to the shore before heading back out to sea.
Fergal O’Shea was one of the people at the beach last Thursday, and he spoke to Lunchtime Live.
He said: “We had just arrived, and we were getting out of the car. We saw a rush of people towards the shoreline, and that’s when we saw the basking shark out there - although we didn’t know it was a basking shark at the time.
“They’re quite big - definitely four-six metres. I don’t think people were necessarily scared of it - it was more of a fascination, really.
“There were a few people in their kayaks out on the water, following them at a distance.”
A crowd of around 50-60 people were on the beach at the time, with some swimmers happily getting back into the water just 5-10 minutes after the sharks swam away.
Fergal said there wasn't any panic - although stressed he wouldn't be jumping into the water with them present.
He said: “I know they’re meant to be pretty harmless, but you’d definitely be a bit intimidated - I wouldn’t be going swimming with them, anyway!
“I was straight out with the Instagram of course - that’s all you can do in that situation!”
While a mention of sharks at the beach may immediately bring to mind Jaws, basking sharks don't pose a major threat to humans - but Hayley Dalton, a PHD student of zoology at Trinity College Dublin, says you should still keep your distance.
She explained: “Basking sharks coming into Achill or the south-east… is quite common in the summer months. Ireland’s waters are one of the best places to see these basking sharks.
“They’re not going to come and hunt you down or try to eat you. They feed on tiny animals called zooplankton, but they’re still very large and powerful animals. You do need to be really careful if you do find yourself near to them.
“If you see basking sharks while you’re out in the water, you just need to keep calm. If you’re swimming… stay on the surface, be calm, and don’t swim after or chase them. That’s the same if you’re in a kayak or paddleboard."
She added it's also important to not block the sharks into the coastline, as they might get scared and dive to get away from the disturbance.