Jellyfish sings have resulted in five people being hospitalised in recent weeks.
An above average number of Lion's Mane jellyfish have been recorded over the summer.
Thankfully its sting is not fatal.
The Lion's Mane jellyfish has been spotted close to high population areas with the forty Foot diving area in Dun Laoghaire a particular hotspot.
The season for them is between June and September and they're often found in cooler water.
Research published by NUI Galway and UCC shows rinsing with vinegar and then applying a heat pack for 40 minutes is the best treatment.