The Cannonball Jellyfish is common on the southeastern coast of the United States, including Hilton Head Island, and is mostly harmless to humans. Swimming among them should not pose a problem.
Contact initiated by humans, especially to the cluster of oral arms at the bottom, may cause the skin to itch slightly, or minor eye irritation. On Hilton Head Island they are extremely abundant in the fall and summer months.
Cannonball Jellyfish are a favorite food of Loggerhead sea turtles.
