Some lucky beachgoers got a rare and unexpected treat at Vancouver's English Bay on Sunday when a grey whale cozied up to the shore.

Kate Loktin was at the beach shortly after noon when she spotted the massive sea mammal. "Took a look out and before I know it this huge spout comes out and there's a whale," she said.

A growing crowd gathered at the shoreline to get a glimpse. A few kayakers followed the whale out into the water, as did one adventurous swimmer.

Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia, warned against such behaviour. "People should be cautious, these are huge animals," he said.

"They've got no appreciation for what one swat of the tail might do, and while the whale may not be aggressive, people can very easily get hurt."

There's no sign the whale is lost or in trouble, Trites added.

"The whale is doing what whales do. It knows how it got here, it knows how to get out."

It wasn't the first sea mammal spotted in Vancouver in recent months. On May 5, a grey whale took a tour through False Creek, wowing crowds.

It meandered through the harbour, travelling east all the way to Science World before heading back out.

A day later, an estimated 150 dolphins frolicked near Horseshoe Bay.

"Species that we know used to be here in large numbers in the past appear to be re-colonizing," Trites said. "They're coming back."

With a report from CTV British Columbia's Penny Daflos