Portuguese Man o' War poses severe risk to European beachgoers

The Portuguese man o' war (Portuguese Galeere) is identified as the most dangerous jellyfish species along European coasts. Its tentacles contain thousands of nematocysts that can inflict intense pain and, in rare cases, be life‑threatening.

Other jellyfish commonly found in European waters include the harmless ear jellyfish, lung jellyfish and egg‑shaped jellyfish. Species such as the fire jellyfish, compass jellyfish and blue jellyfish can cause painful skin reactions but are not fatal. Swimmers are advised to recognize the more hazardous species and to leave the water promptly if stung, seeking appropriate medical care.

The overview aims to help holidaymakers in the Mediterranean, Atlantic, North Sea and Baltic regions identify which jellyfish require caution and how to respond to stings.