The horrifying incident took place at the Steveston Fisherman’s Wharf in Richmond B.C., in Canada, as tourists watched the animal looking for fish.
Footage shows people laughing as the sea lion bobs up and down in the water.
At one point it jumps right up to a young girl who was leaning over the side of the pier to get a better look.
She flinches back and giggles – seemingly thinking the animal is being playful – before sitting at the water’s edge.
But the sea lion then leaps from the water grabs her by the dress before pulling her in.
Onlookers gasp and scream as a man, believed to be a relative, jumps fully clothed into the harbour to rescue her.
He lifts her to safety before climbing out himself – clearly shaken by the incident.
The sea lion does not reappear as the completely drenched young girl is led away by relatives.
The video was captured by Michael Fujiwara, from Vancouver, who told the Vancouver Sun: ‘I was just sitting by the dock and then this sea lion popped its head out of the water just in front of me. I just took out my cell phone and started filming.
‘The sea lion actually attracted a lot of attention from the visitors there, including the young girl.
‘She and her family, I guess, they came, they started feeding the animal bread crumbs or whatever it was, and then I guess the animal got a little too comfortable.’
Sea Lions are highly intelligent creatures and are generally thought to be timid in nature.
There have been reports of aggressive attacks on humans in the past though it is not known if the animal was trying to harm the girl.
The animal leaps out of the water before grabbing a young girl sitting at the side of the pier by her dress
The girl is pulled over the side of the pier with great force as onlookers scream in terror
The girl was only in the water for a couple of seconds before being rescued
A man lifts the girl out of the water after leaping in fully clothed to save her. The sea lion does not resurface