The wild boar surprised beachgoers at Schönagen Strand, Schleswig-Holstein, at the weekend.
Footage shows people on the beach watch as two ears and a snout poke above the water.
Shouts of "laufen" can be heard, which means "run" in German.
A man can be seen standing by the shore with a spade. When the boar suddenly emerges from the water he tries to run before turning around to shoo the boar with it.
The video shows sunbathers run as the boar rummages around beach towels and chairs.
German Life Saving Association (DLRG) watchdog leader told Bild newspaper he thought the boar was a "dog" at first.
After spotting the animal swimming in the sea with a pair of binoculars, he rounded up all DLRG forces on the beach.
"Then we pulled the guests out of the water and brought the children to safety," he said.
Claus Schlüter from Cuxhaven told NDR the boar had been swimming for miles before he encouraged it to change course towards Shonagen Strand.
It comes after another wild boar caused some disruption after it snatched a man's laptop bag causing the naked owner to chase the boar around a sunbathing spot in Berlin.
Adele Landauer, an actor and life coach, captured the hilarious scene as the man scrambled to recover his computer from the boar, who was running around with two piglets in tow.
