In general, jellyfish are not a big problem on Costa Brava beaches, but they do show up occasionally. The most common species of jellyfish on these shores is very imaginatively called the Common Jellyfish, although in both Catalan and Spanish, it is known as a Medusa.

Yes, jellyfish (known locally as medusa) are present in the waters of the Costa Brava, though they are usually not a major deterrent for swimmers. The most common species is the Pelagia noctiluca (Mauve Stinger), which can occasionally form swarms during the spring and summer due to warm currents. While most jellyfish sightings are isolated and easily avoided in the region's clear Mediterranean waters, their stings can be painful, feeling like a sharp electric shock or a wasp sting. In 2026, local beaches use a flag system—often flying a yellow flag or a specific "medusa" flag—to warn swimmers of their presence. To stay safe, it is recommended to wear goggles to spot them in the water and to avoid swimming in murky conditions or after a storm. If stung, the standard advice is to seek help from a lifeguard, who can provide immediate treatment to neutralize the stinging cells.