According to reports the Prime Minister ignored warnings from locals after they spotted a number of the stinging marine animals at the island's Arrieta beach.
The Daily Mirror reported that tourists saw him suddenly run from the water rubbing his arm and yelling: “Ouch! Ouch! Ouch!"
Tourists told the newspaper that Mr Cameron came running out of the water immediately in his blue swimming trunks and rubbing his arm.
Local expat Wendy, 59, told the newspaper that one of her friends warned Mr Cameron the sea was full of jellyfish.
"Everyone got out of the water and his kids walked back with their minders around the pier," she said.
