Swimmers are being urged to be careful after several people have been rushed to hospital with Lion's man jellyfish stings.
Marine Biologist and UCC lecturer, Dr Tom Doyle said on Twitter that they look very big for this time of year.
"Really big ones for this time of year so looks like they have overwintered."
Lots washing up in Ireland too. Really big ones for this time of year so looks like they have overwintered.
— Tom Doyle (@tomkdoyle) June 17, 2018
According to Independent.ie, three people were hospitalised last week with one member of Galway swimming club taken to A&E after a bad sting.
"They are really putting a dampener on open water swimming this season and even the most seasoned of swimmers are wary of going into the water at the moment."
A spokesperson for Galway Swimming Club said, "We have had only one member who had to go to A&E for treatment, but we have had several members who have gotten stung from these particular bad jellies."
The club has advised swimmers to stay inside the designated bathing areas (DBA's) where lifeguards can help them if they get stung.
"Our advice is to swim at the DBA’s as lifeguards ensure your safety on our beaches," they said in a statement on Facebook.
"The sting from these jellyfish can cause anaphylactic shock and we have had a number of people hospitalised as a result of a sting from these venomous Jellyfish over the years."
"Members of the public can use wetsuits to minimise the risk of being stung by them. They can also use rash vests and use Vaseline on their faces and hands."
Galway Water Safety said the increase in jellyfish could be down to the warmer weather and a lack of predators to feed on them.
If you do get stung, rinse the area with vinegar, pluck the visible tentacles with a tweezers and immerse the area in 45-degree water for 20-45 minutes.
Do NOT pee on the area - this is not an episode of Friends, lads,